Asp.net MVC Uploaded CSV file data showing as json - asp.net

I have tried to upload a csv file to my application but this not showing all rows, I am geting only one row here is my code
Model
public class FileUploadViewModel
{
public string Name { get; set; }
public string School { get; set; }
public string Age { get; set; }
public string DOB { get; set; }
public string ParentName { get; set; }
}
Controller
[HttpPost]
public ActionResult AddparcelView(FileUploadViewModel filedata)
{
var attachedFile = System.Web.HttpContext.Current.Request.Files["CsvDoc"];
if (attachedFile == null || attachedFile.ContentLength <= 0) return Json(null);
var csvReader = new StreamReader(attachedFile.InputStream);
var uploadModelList = new List<FileUploadViewModel>();
string inputDataRead;
var values = new List<string>();
var uploadModelRecord = new FileUploadViewModel();
var jsonToOutput = "";
while ((inputDataRead = csvReader.ReadLine()) != null)
{
values.Add(inputDataRead.Trim().Replace(" ", "").Replace(",", " "));
}
values.Remove(values[0]);
values.Remove(values[values.Count - 1]);
var i = 0;
foreach (var value in values)
{
i++;
var eachValue = value.Split(' ');
uploadModelRecord.Name = eachValue[0] != "" ? eachValue[0] : string.Empty;
uploadModelRecord.School = eachValue[1] != "" ? eachValue[1] : string.Empty;
uploadModelRecord.Age = eachValue[2] != "" ? eachValue[2] : string.Empty;
uploadModelRecord.DOB = eachValue[3] != "" ? eachValue[3] : string.Empty;
uploadModelRecord.ParentName = eachValue[4] != "" ? eachValue[4] : string.Empty;
//jsonToOutput = JsonConvert.SerializeObject(uploadModelRecord, Formatting.Indented);
Console.WriteLine(i);
}
return Json(uploadModelRecord);
}
I have five rows at this CSV file but i getting only one row like this
Age: "sdfdsf"
DOB: "test"
Name:"mohammad2"
ParentName:"test"
School:"32"
So this is just one row data I am showing up with json, but i not getting the full json array with other 4rows please help me, Thanks

You are using the same instance uploadModelRecord in every iteration of your loop. In the first iteration it gets the values of the first line. In the second iteration those values get overwritten with the values of the second line. And so on.
Create a new instance in each iteration and add them to a list. Return the serialized list.
public ActionResult AddparcelView(FileUploadViewModel filedata)
{
...
//Remove line for variable uploadModelRecord.
var uploadModelRecords = new List<FileUploadViewModel>(); //List instead of single element.
foreach (var value in values)
{
i++;
var eachValue = value.Split(' ');
var uploadModelRecord = new FileUploadViewModel(); //Variable for current line.
uploadModelRecord.Name = eachValue[0] != "" ? eachValue[0] : string.Empty;
uploadModelRecord.School = eachValue[1] != "" ? eachValue[1] : string.Empty;
uploadModelRecord.Age = eachValue[2] != "" ? eachValue[2] : string.Empty;
uploadModelRecord.DOB = eachValue[3] != "" ? eachValue[3] : string.Empty;
uploadModelRecord.ParentName = eachValue[4] != "" ? eachValue[4] : string.Empty;
//jsonToOutput = JsonConvert.SerializeObject(uploadModelRecord, Formatting.Indented);
Console.WriteLine(i);
uploadModelRecords.Add(uploadModelRecord); //Here you add the variable for current line to the list.
}
return Json(uploadModelRecords); //Return the list instead of a single instance.
}

Related

Xunit CSV streamReader.ReadToEnd returns System.ArgumentOutOfRangeException

I would like to evaluate a CSV data series with Xunit.
For this I need to read in a string consisting of int, bool, double and others.
With the following code, the transfer basically works for one row.
But since I want to test for predecessor values, I need a whole CSV file for evaluation.
My [Theory] works with InlineData without errors.
But when I read in a CSV file, the CSVDataHandler gives a System.ArgumentOutOfRangeException!
I can't find a solution for the error and ask for support.
Thanks a lot!
[Theory, CSVDataHandler(false, "C:\\MyTestData.txt", Skip = "")]
public void TestData(int[] newLine, int[] GetInt, bool[] GetBool)
{
for (int i = 0; i < newLine.Length; i++)
{
output.WriteLine("newLine {0}", newLine[i]);
output.WriteLine("GetInt {0}", GetInt[i]);
output.WriteLine("GetBool {0}", GetBool[i]);
}
}
[DataDiscoverer("Xunit.Sdk.DataDiscoverer", "xunit.core")]
[AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
public abstract class DataArribute : Attribute
{
public abstract IEnumerable<object> GetData(MethodInfo methodInfo);
public virtual string? Skip { get; set; }
}
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class CSVDataHandler : DataAttribute
{
public CSVDataHandler(bool hasHeaders, string pathCSV)
{
this.hasHeaders = hasHeaders;
this.pathCSV = pathCSV;
}
public override IEnumerable<object[]> GetData(MethodInfo methodInfo)
{
var methodParameters = methodInfo.GetParameters();
var paramterTypes = methodParameters.Select(p => p.ParameterType).ToArray();
using (var streamReader = new StreamReader(pathCSV))
{
if (hasHeaders) { streamReader.ReadLine(); }
string csvLine = string.Empty;
// ReadLine ++
//while ((csvLine = streamReader.ReadLine()) != null)
//{
// var csvRow = csvLine.Split(',');
// yield return ConvertCsv((object[])csvRow, paramterTypes);
//}
// ReadToEnd ??
while ((csvLine = streamReader.ReadToEnd()) != null)
{
if (Environment.NewLine != null)
{
var csvRow = csvLine.Split(',');
yield return ConvertCsv((object[])csvRow, paramterTypes); // System.ArgumentOutOfRangeException
}
}
}
}
private static object[] ConvertCsv(IReadOnlyList<object> cswRow, IReadOnlyList<Type> parameterTypes)
{
var convertedObject = new object[parameterTypes.Count];
for (int i = 0; i < parameterTypes.Count; i++)
{
convertedObject[i] = (parameterTypes[i] == typeof(int)) ? Convert.ToInt32(cswRow[i]) : cswRow[i]; // System.ArgumentOutOfRangeException
convertedObject[i] = (parameterTypes[i] == typeof(double)) ? Convert.ToDouble(cswRow[i]) : cswRow[i];
convertedObject[i] = (parameterTypes[i] == typeof(bool)) ? Convert.ToBoolean(cswRow[i]) : cswRow[i];
}
return convertedObject;
}
}
MyTestData.txt
1,2,true,
2,3,false,
3,10,true,
The first call to streamReader.ReadToEnd() will return the entire contents of the file in a string, not just one line. When you call csvLine.Split(',') you will get an array of 12 elements.
The second call to streamReader.ReadToEnd() will not return null as your while statement appears to expect, but an empty string. See the docu at
https://learn.microsoft.com/en-us/dotnet/api/system.io.streamreader.readtoend?view=net-7.0
If the current position is at the end of the stream, returns an empty
string ("").
With the empty string, the call to call csvLine.Split(',') will return an array of length 0, which causes your exception when its first element (index 0) is accessed.
All of this could have been easily discovered by simply starting the test in a debugger.
It looks like you have some other issues here as well.
I don't understand what your if (Environment.NewLine != null) is intended to do, the NewLine property will never be null but should have one of the values "\r\n" or "\n" so the if will always be taken.
The parameters of your test method are arrays int[] and bool[], but you are checking against the types int, double and bool in your ConvertCsv method, so the alternative cswRow[i] will always be returned. You'll wind up passing strings to your method expecting int[] and bool[] and will at latest get an error there.
This method reads a data series from several rows and columns and returns it as an array for testing purposes.
The conversion of the columns can be adjusted according to existing pattern.
Thanks to Christopher!
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class CSVDataHandler : Xunit.Sdk.DataAttribute
{
public CSVDataHandler(string pathCSV)
{
this.pathCSV = pathCSV;
}
public override IEnumerable<object[]> GetData(MethodInfo methodInfo)
{
List<int> newLine = new();
List<int> GetInt = new();
List<bool> GetBool = new();
var reader = new StreamReader(pathCSV);
string readData = string.Empty;
while ((readData = reader.ReadLine()) != null)
{
string[] split = readData.Split(new char[] { ',' });
newLine.Add(int.Parse(split[0]));
GetInt.Add(int.Parse(split[1]));
GetBool.Add(bool.Parse(split[2]));
// Add more objects ...
}
yield return new object[] { newLine.ToArray(), GetInt.ToArray(), GetBool.ToArray() };
}
}

.NET MVC Linq pagination with PagedList

In my MVC app I'm using LINQ to retrieve data from DB and PagedList for pagination. I have a couple of questions, after the code block, that I would like some help with.
Function where I retrieve data from cache or DB:
public NewsPagedListDTO GetNewsFromCacheOrDB(int pageSize, int? newsID, int? page, string newsTitle, int? categoryID, int? orderByTitle, int? orderByPublisher, int? orderByDate, int? orderByCategory)
{
DataCache cache = new DataCache("default");
object cacheNews = cache.Get("cacheNews");
List<News> news = new List<News>();
if (cacheNews == null)
{
news = (from n in DB.News
select n).ToList();
//Only cache if no parameters was provided
if (newsID == null && newsTitle == null && categoryID == null && orderByTitle == null && orderByPublisher == null &&
orderByDate == null && orderByCategory == null)
cache.Add("cacheNews", news);
}
}
else
{
news = (List<News>)cacheNews;
}
if (newsID != null)
news = news.Where(n => n.NewsID == newsID).ToList();
if (categoryID != null)
news = news.Where(n => n.CategoryID == categoryID).ToList();
if (newsTitle != null)
news = news.Where(n => n.Title == newsTitle).ToList();
if (orderByTitle != null)
if (orderByTitle == 0)
news = news.OrderBy(n => n.Title).ToList();
else
news = news.OrderByDescending(n => n.Title).ToList();
if (orderByPublisher != null)
if (orderByPublisher == 0)
news = news.OrderBy(n => n.PublishedByFullName).ToList();
else
news = news.OrderByDescending(n => n.PublishedByFullName).ToList();
if (orderByDate != null)
if (orderByDate == 0)
news = news.OrderByDescending(n => n.DatePublished).ToList();
else
news = news.OrderBy(n => n.DatePublished).ToList();
if (orderByCategory != null)
if (orderByCategory == 0)
news = news.OrderBy(n => n.CategoryToString).ToList();
else
news = news.OrderByDescending(n => n.CategoryToString).ToList();
List<NewsDTO> newsDTO = new List<NewsDTO>();
foreach (var item in news)
{
NewsDTO newsDTOtemp = new NewsDTO();
newsDTOtemp.BlobName = item.BlobName;
newsDTOtemp.DatePublished = item.DatePublished;
newsDTOtemp.NewsID = item.NewsID;
newsDTOtemp.PreviewText = item.PreviewText;
newsDTOtemp.PublishedByEmail = item.PublishedByEmail;
newsDTOtemp.PublishedByFullName = item.PublishedByFullName;
newsDTOtemp.PublishedByID = item.PublishedByID;
newsDTOtemp.Title = item.Title;
newsDTOtemp.CategoryID = item.Category.CategoryID;
newsDTOtemp.CategoryToString = item.Category.Name;
newsDTO.Add(newsDTOtemp);
}
//Pagination
NewsPagedListDTO newsResultDTO = new NewsPagedListDTO();
newsResultDTO.NewsDTO = (PagedList<NewsDTO>)newsDTO.ToPagedList(page ?? 1, pageSize);
return newsResultDTO;
}
Pagination in my view:
#Html.PagedListPager(Model.NewsPagedListDTO.NewsDTO, page => Url.Action("News", new
{
page,
newsTitle = Request.QueryString["NewsTitle"],
categoryID = Request.QueryString["categoryID"],
orderByTitle = Request.QueryString["orderByTitle"],
orderByPublisher = Request.QueryString["orderByPublisher"],
orderByDate = Request.QueryString["orderByDate"],
orderByCategory = Request.QueryString["orderByCategory"]
}),
new PagedListRenderOptions()
{
Display = PagedListDisplayMode.IfNeeded,
MaximumPageNumbersToDisplay = 5,
DisplayEllipsesWhenNotShowingAllPageNumbers = false,
DisplayLinkToPreviousPage = PagedListDisplayMode.Never,
DisplayLinkToNextPage = PagedListDisplayMode.Never,
LinkToFirstPageFormat = String.Format("«"),
LinkToLastPageFormat = String.Format("»")
})
Questions
It's the first time I'm using PagedList. What's the point in having postback for changing the page when the full results is retrieved? Isn't it better with client side pagination then? Currently I am retrieving all posts from DB with:
news = (from n in DB.News
select n).ToList();
And after data is retrieved, sort with parameters..
Sure the result is easy to cache but.. I rather only get data for just one page.
How would I only get data for the current page with my optional parameters? I have used stored procedures for this before but I don't think it's possible with PagedList.
How can I have cleaner code for optional parameters in my LINQ query? I don't like all those if statements..
The thing is you have to Skip items and then Take(pageSize)
var pagedNews = DB.News.Skip((currentPage - 1) * pageSize).Take(pageSize).ToList();
So let's say you have 5 items / page.
If you are on page 1
(1 - 1) * 5 = 0 so skip zero Items and take 5
If you are on page 2
(2 - 1) * 5 = 5 so skip 5 Items and take 5
Your parameters are Nullable so you might have to put a default condition on your parameters say if NULL then PageSize = 5 and PageNumber = 1
int pageSize, int? newsID, int? page
EDIT:
Instead of:
if (cacheNews == null)
{
news = (from n in DB.News
select n).ToList();
...........
}
Use this:
// You will have to OrderBy() before doing the pagination:
// Read as Queryable()
var pagedNews = DB.News.AsQueryable();
// Apply OrderBy Logic
pagedNews = pagedNews.OrderBy();
//ApplyPagination
pagedNews = pagedNews.Skip((currentPage - 1) * pageSize).Take(pageSize).ToList();
ORDER BY
You don't need to pass the OrderBy columns as separate strings.
Pass one string e.g. selectedSortBy from View,
I have created a Helper method:
using System;
using System.Linq;
using System.Linq.Expressions;
namespace Common.Helpers
{
public static class PaginationHelper
{
public static IQueryable<T> ApplyPagination<T>(IQueryable<T> source, Pagination pagination)
{
var sortDirection = pagination.SortDirection == SortDirectionEnum.Ascending ? "OrderBy" : "OrderByDescending";
var orderBy = pagination.SortBy ?? pagination.DefaultSortBy;
return source.OrderBy(orderBy, sortDirection).Skip((pagination.PageNumber - 1) * pagination.PageSize).Take(pagination.PageSize);
}
public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string ordering, string sortDirection, params object[] values)
{
var type = typeof(T);
var property = type.GetProperty(ordering);
var parameter = Expression.Parameter(type, "p");
var propertyAccess = Expression.MakeMemberAccess(parameter, property);
var orderByExp = Expression.Lambda(propertyAccess, parameter);
var resultExp = Expression.Call(typeof(Queryable), sortDirection, new Type[] { type, property.PropertyType }, source.Expression, Expression.Quote(orderByExp));
return source.Provider.CreateQuery<T>(resultExp);
}
}
}
Pagination Model + Enum:
namespace Common.Helpers
{
public class Pagination
{
public SortDirectionEnum SortDirection { get; set; }
public string SortBy { get; set; }
public int TotalRecords { get; set; }
public int NumberOfPages { get; set; }
public int PageSize { get; set; }
public int PageNumber { get; set; }
public string DefaultSortBy { get; set; }
public string ReloadUrl { get; set; }
public string TargetDiv { get; set; }
public Pagination()
{
}
public Pagination(string reloadUrl, string targetDiv, int totalRecords, int numberOfPages)
{
ReloadUrl = reloadUrl;
TargetDiv = targetDiv;
PageSize = 10;
PageNumber = 1;
}
}
public enum SortDirectionEnum
{
Ascending = 1,
Descending = 2
}
}
Then call your Query like this:
var items = DB.News.AsQueryable();
items = PaginationHelper.ApplyPagination(items, PAGINATION_MODEL);

Dapper: Mapping dynamic pivot columns from stored procedure

My stored procedure is returning dynamic pivot columns as available. I am using the SQLMapper and COlumnTypeAttribute, But in the results I can only see the first column and its value, but the dynamic pivot column(s) and their values(s) are empty.
the sample data could look like
The first column is fixed, Rest of the columns are pivot columns.
TSBNumber SystemXY SystemBB SystemTT
asdas 1/1/2013
1231 1/1/2014
12312 1/1/2013
ASAWS 1/1/2013
awsdS 1/1/2013
Store Procedure
DECLARE #PivotColumnHeaders NVARCHAR(MAX)
SELECT #PivotColumnHeaders =
COALESCE(
#PivotColumnHeaders + ',[' + cast(SystemFullName as Nvarchar) + ']',
'[' + cast(SystemFullName as varchar)+ ']'
)
FROM System
WHERE (#SelectedSystemIDs IS NULL OR System.ID IN(select * from dbo.SplitInts_RBAR_1(#SelectedSystemIDs, ',')))
AND ((#PlatformID IS NULL) OR (System.PlatformID = #PlatformID) OR (#PlatformID = 12 AND System.PlatformID <= 2))
DECLARE #PivotTableSQL NVARCHAR(MAX)
SET #PivotTableSQL = N'
SELECT *
FROM (
SELECT
TSBNumber [TSBNumber],
SystemFullName,
ClosedDate
FROM ServiceEntry
INNER JOIN System
ON ServiceEntry.SystemID = System.ID
where
(ServiceEntry.TSBNumber IS NOT NULL)
AND
(ServiceEntry.ClosedDate IS NOT NULL)
AND
(
(''' + #SelectedTsbIDs + ''' = '''+ '0' + ''') OR
(ServiceEntry.TSBNumber in (select * from dbo.SplitStrings_Moden(''' + #SelectedTsbIDs + ''', ''' + ',' + ''')))
)
) AS PivotData
PIVOT (
MAX(ClosedDate)
FOR SystemFullName IN (
' + #PivotColumnHeaders + '
)
) AS PivotTable
'
EXECUTE (#PivotTableSQL)
ColumnAttributeTypeManager
namespace RunLog.Domain.Exports
{
/// <summary>
/// Uses the Name value of the ColumnAttribute specified, otherwise maps as usual.
/// </summary>
/// <typeparam name="T">The type of the object that this mapper applies to.</typeparam>
public class ColumnAttributeTypeMapper<T> : FallbackTypeMapper
{
public static readonly string ColumnAttributeName = "ColumnAttribute";
public ColumnAttributeTypeMapper()
: base(new SqlMapper.ITypeMap[]
{
new CustomPropertyTypeMap(
typeof(T),
(type, columnName) =>
type.GetProperties().FirstOrDefault(prop =>
prop.GetCustomAttributes(false)
.OfType<ColumnAttribute>()
.Any(attr => attr.Name == columnName)
)
),
new DefaultTypeMap(typeof(T))
})
{
}
//public ColumnAttributeTypeMapper()
// : base(new SqlMapper.ITypeMap[]
// {
// new CustomPropertyTypeMap(typeof (T), SelectProperty),
// new DefaultTypeMap(typeof (T))
// })
//{
//}
//private static PropertyInfo SelectProperty(Type type, string columnName)
//{
// return
// type.GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance).
// FirstOrDefault(
// prop =>
// prop.GetCustomAttributes(false)
// // Search properties to find the one ColumnAttribute applied with Name property set as columnName to be Mapped
// .Any(attr => attr.GetType().Name == ColumnAttributeName
// &&
// attr.GetType().GetProperties(BindingFlags.Public |
// BindingFlags.NonPublic |
// BindingFlags.Instance)
// .Any(
// f =>
// f.Name == "Name" &&
// f.GetValue(attr).ToString().ToLower() == columnName.ToLower()))
// && // Also ensure the property is not read-only
// (prop.DeclaringType == type
// ? prop.GetSetMethod(true)
// : prop.DeclaringType.GetProperty(prop.Name,
// BindingFlags.Public | BindingFlags.NonPublic |
// BindingFlags.Instance).GetSetMethod(true)) != null
// );
//}
}
public class MyModel
{
[Column("TSBNumber")]
public string TSBNumber { get; set; }
[Column(Name = "FileKey")]
public string MyProperty2 { get; set; }
//public string MyProperty2 { get; set; } // Uses Default Mapping
// ...
}
[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)]
public class ColumnAttribute : Attribute
{
public string Name { get; set; }
public ColumnAttribute() { }
public ColumnAttribute(string Name) { this.Name = Name; }
}
public class FallbackTypeMapper : SqlMapper.ITypeMap
{
private readonly IEnumerable<SqlMapper.ITypeMap> _mappers;
public FallbackTypeMapper(IEnumerable<SqlMapper.ITypeMap> mappers)
{
_mappers = mappers;
}
public ConstructorInfo FindConstructor(string[] names, Type[] types)
{
foreach (var mapper in _mappers)
{
try
{
ConstructorInfo result = mapper.FindConstructor(names, types);
if (result != null)
{
return result;
}
}
catch (NotImplementedException)
{
}
}
return null;
}
public SqlMapper.IMemberMap GetConstructorParameter(ConstructorInfo constructor, string columnName)
{
foreach (var mapper in _mappers)
{
try
{
var result = mapper.GetConstructorParameter(constructor, columnName);
if (result != null)
{
return result;
}
}
catch (NotImplementedException)
{
}
}
return null;
}
public SqlMapper.IMemberMap GetMember(string columnName)
{
foreach (var mapper in _mappers)
{
try
{
var result = mapper.GetMember(columnName);
if (result != null)
{
return result;
}
}
catch (NotImplementedException)
{
}
}
return null;
}
}
}
Executing Stored Procedure
public static string ServiceTsbExport(DateTime StartDate, DateTime EndDate, int UserRoleID,
string SelectedSystemIDs,
string SelectedTsbIDs)
{
EFDbContext db = new EFDbContext();
Dapper.SqlMapper.SetTypeMap(typeof(MyModel), new ColumnAttributeTypeMapper<MyModel>());
return db.Database.SqlQuery<MyModel>("[dbo].[spExportServiceTSB] #parm1, #parm2, #parm3, #parm4, #parm5",
new SqlParameter("parm1", StartDate),
new SqlParameter("parm2", EndDate),
new SqlParameter("parm3", SelectedSystemIDs),
new SqlParameter("parm4", SelectedTsbIDs),
new SqlParameter("parm5", UserRoleID)
).ToList().ToHTMLTable();
}
I think you're making this very hard while it could be simple. I've once done almost exactly the same thing. Here's an anonymized version of it:
using Dapper;
...
using (var cnn = new SqlConnection(#"Data Source=... etc."))
{
cnn.Open();
var p = new DynamicParameters();
p.Add("#params", "Id=21");
var obs = cnn.Query(sql:"GetPivotData", param: p,
commandType:CommandType.StoredProcedure);
var dt = ToDataTable(obs);
}
This ToDataTable method is probably similar to your ToHTMLTable method. Here it is:
public DataTable ToDataTable(IEnumerable<dynamic> items)
{
if (items == null) return null;
var data = items.ToArray();
if (data.Length == 0) return null;
var dt = new DataTable();
foreach(var pair in ((IDictionary<string, object>)data[0]))
{
dt.Columns.Add(pair.Key, (pair.Value ?? string.Empty).GetType());
}
foreach (var d in data)
{
dt.Rows.Add(((IDictionary<string, object>)d).Values.ToArray());
}
return dt;
}
The heart of the logic is that the dynamic returned by Dapper's Query() extension method can be cast to an IDictionary<string, object>.

How to create auto generate id for ListOf rows returned

I am accessing list of data as shown below.
var result = (from Pages in PagesList.Items.OfType<SPListItem>()
select new ListImages
{
desc = Convert.ToString(Pages["Description"])
}).ToList();
What I want is to auto generate customized increamental id for the no of rows generated.
ex, slide-img-1, slide-img-2 etc.
public class ListImages
{
string _desc;
string _id;
public string id
{
get
{
if (_id != null)
return _id;
else
return string.Empty;
}
set { _id = value; }
}
public string desc
{
get
{
if (_desc != null)
return _desc;
else
return string.Empty;
}
set { _desc = value; }
}
}
Thanks,
Ashish
I don't know if it can be achieved with the Linq specific syntax, but writing your query like this, you could use the .Select() method that provides an index:
var result = PagesList.Items.OfType<SPListItem>()
.Select((page, index) => new ListImages
{
desc = Convert.ToString(page["Description"]),
id = String.Concat("slide-img-", index + 1)
})
.ToList();

Sorting IQueryable date column by string value in LINQ

I am trying to sort an IQueryable object by a specific column via a string input.
Calling .ToList() on the IQueryable and sorting via a list column works perfectly, however when sorting a date column, it sorts alphabetically, which is not ideal.
If anybody could point me in the correct direction here, I'd appreciate it.
My Usage
IQueryable<MyItemType> list = (from t1 in db.MyTable
select t1);
List<MyItemType> itemsSorted; // Sort here
if (!String.IsNullOrEmpty(OrderBy))
{
itemsSorted = list.OrderBy(OrderBy).ToList();
}
else
{
itemsSorted = list.ToList();
}
Extension Method
using System.Linq;
using System.Collections.Generic;
using System;
using System.Linq.Expressions;
using System.Reflection;
public static class OrderByHelper
{
public static IEnumerable<T> OrderBy<T>(this IEnumerable<T> enumerable, string orderBy)
{
return enumerable.AsQueryable().OrderBy(orderBy).AsEnumerable();
}
public static IQueryable<T> OrderBy<T>(this IQueryable<T> collection, string orderBy)
{
foreach (OrderByInfo orderByInfo in ParseOrderBy(orderBy))
collection = ApplyOrderBy<T>(collection, orderByInfo);
return collection;
}
private static IQueryable<T> ApplyOrderBy<T>(IQueryable<T> collection, OrderByInfo orderByInfo)
{
string[] props = orderByInfo.PropertyName.Split('.');
Type type = typeof(T);
ParameterExpression arg = Expression.Parameter(type, "x");
Expression expr = arg;
foreach (string prop in props)
{
// use reflection (not ComponentModel) to mirror LINQ
PropertyInfo pi = type.GetProperty(prop);
expr = Expression.Property(expr, pi);
type = pi.PropertyType;
}
Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), type);
LambdaExpression lambda = Expression.Lambda(delegateType, expr, arg);
string methodName = String.Empty;
if (!orderByInfo.Initial && collection is IOrderedQueryable<T>)
{
if (orderByInfo.Direction == SortDirection.Ascending)
methodName = "ThenBy";
else
methodName = "ThenByDescending";
}
else
{
if (orderByInfo.Direction == SortDirection.Ascending)
methodName = "OrderBy";
else
methodName = "OrderByDescending";
}
//TODO: apply caching to the generic methodsinfos?
return (IOrderedQueryable<T>)typeof(Queryable).GetMethods().Single(
method => method.Name == methodName
&& method.IsGenericMethodDefinition
&& method.GetGenericArguments().Length == 2
&& method.GetParameters().Length == 2)
.MakeGenericMethod(typeof(T), type)
.Invoke(null, new object[] { collection, lambda });
}
private static IEnumerable<OrderByInfo> ParseOrderBy(string orderBy)
{
if (String.IsNullOrEmpty(orderBy))
yield break;
string[] items = orderBy.Split(',');
bool initial = true;
foreach (string item in items)
{
string[] pair = item.Trim().Split(' ');
if (pair.Length > 2)
throw new ArgumentException(String.Format("Invalid OrderBy string '{0}'. Order By Format: Property, Property2 ASC, Property2 DESC", item));
string prop = pair[0].Trim();
if (String.IsNullOrEmpty(prop))
throw new ArgumentException("Invalid Property. Order By Format: Property, Property2 ASC, Property2 DESC");
SortDirection dir = SortDirection.Ascending;
if (pair.Length == 2)
dir = ("desc".Equals(pair[1].Trim(), StringComparison.OrdinalIgnoreCase) ? SortDirection.Descending : SortDirection.Ascending);
yield return new OrderByInfo() { PropertyName = prop, Direction = dir, Initial = initial };
initial = false;
}
}
private class OrderByInfo
{
public string PropertyName { get; set; }
public SortDirection Direction { get; set; }
public bool Initial { get; set; }
}
private enum SortDirection
{
Ascending = 0,
Descending = 1
}
public static IQueryable<T> OrderByIQueryableStringValue<T>(this IQueryable<T> source, string ordering, params object[] values)
{
var type = typeof(T);
var property = type.GetProperty(ordering);
var parameter = Expression.Parameter(type, "p");
var propertyAccess = Expression.MakeMemberAccess(parameter, property);
var orderByExp = Expression.Lambda(propertyAccess, parameter);
MethodCallExpression resultExp = Expression.Call(typeof(Queryable), "OrderBy", new Type[] { type, property.PropertyType }, source.Expression, Expression.Quote(orderByExp));
return source.Provider.CreateQuery<T>(resultExp);
}
}
If you want there is already a library for dynamic linq that has a order by extension method (and others linq methods) that accepts string input for all the data types. See http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx

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