Converting List in Comma Separated List with linq? - asp.net

Question

I am having a info class with following field like id,name,address and i have created list of that info like List.
I want to have all the values of list into comma seperated strings using linq. Is there any way for this.

Answer 1

simple way... may not be the fastest so it depends on how many records you are processing
var myObjects = new[] {
new {
id=1,
name="Matt",
address="1234 no chance ln\r\nnowhere, OH 12345"
},
new {
id=1,
name="Jim",
address="4321 no chance ln\r\nnowhere, OH 12345"
}
};
var myList = (from o in myObjects
select string.Format("{0},\"{1}\",\"{2}\"",
o.id,
o.name,
(o.address ?? string.Empty).Replace("\r\n", ";")
)).ToList();

Answer 2

Have a look at this example by Mike Hadlow. It needs some improvement (escaping commas, new line support etc) but gives you the basic idea.

Answer 3

Taken from the LinQExtensions.cs found at Batch Updates and Deletes with LINQ to SQL
/// <summary>
/// Creates a *.csv file from an IQueryable query, dumping out the 'simple' properties/fields.
/// </summary>
/// <param name="query">Represents a SELECT query to execute.</param>
/// <param name="fileName">The name of the file to create.</param>
/// <remarks>
/// <para>If the file specified by <paramref name="fileName"/> exists, it will be deleted.</para>
/// <para>If the <paramref name="query"/> contains any properties that are entity sets (i.e. rows from a FK relationship) the values will not be dumped to the file.</para>
/// <para>This method is useful for debugging purposes or when used in other utilities such as LINQPad.</para>
/// </remarks>
public static void DumpCSV(this IQueryable query, string fileName)
{
query.DumpCSV(fileName, true);
}
/// <summary>
/// Creates a *.csv file from an IQueryable query, dumping out the 'simple' properties/fields.
/// </summary>
/// <param name="query">Represents a SELECT query to execute.</param>
/// <param name="fileName">The name of the file to create.</param>
/// <param name="deleteFile">Whether or not to delete the file specified by <paramref name="fileName"/> if it exists.</param>
/// <remarks>
/// <para>If the <paramref name="query"/> contains any properties that are entity sets (i.e. rows from a FK relationship) the values will not be dumped to the file.</para>
/// <para>This method is useful for debugging purposes or when used in other utilities such as LINQPad.</para>
/// </remarks>
public static void DumpCSV(this IQueryable query, string fileName, bool deleteFile)
{
if (File.Exists(fileName) && deleteFile)
{
File.Delete(fileName);
}
using (var output = new FileStream(fileName, FileMode.CreateNew))
{
using (var writer = new StreamWriter(output))
{
var firstRow = true;
PropertyInfo[] properties = null;
FieldInfo[] fields = null;
Type type = null;
bool typeIsAnonymous = false;
foreach (var r in query)
{
if (type == null)
{
type = r.GetType();
typeIsAnonymous = type.IsAnonymous();
properties = type.GetProperties();
fields = type.GetFields();
}
var firstCol = true;
if (typeIsAnonymous)
{
if (firstRow)
{
foreach (var p in properties)
{
if (!firstCol) writer.Write(",");
else { firstCol = false; }
writer.Write(p.Name);
}
writer.WriteLine();
}
firstRow = false;
firstCol = true;
foreach (var p in properties)
{
if (!firstCol) writer.Write(",");
else { firstCol = false; }
DumpValue(p.GetValue(r, null), writer);
}
}
else
{
if (firstRow)
{
foreach (var p in fields)
{
if (!firstCol) writer.Write(",");
else { firstCol = false; }
writer.Write(p.Name);
}
writer.WriteLine();
}
firstRow = false;
firstCol = true;
foreach (var p in fields)
{
if (!firstCol) writer.Write(",");
else { firstCol = false; }
DumpValue(p.GetValue(r), writer);
}
}
writer.WriteLine();
}
}
}
}
private static void DumpValue(object v, StreamWriter writer)
{
if (v != null)
{
switch (Type.GetTypeCode(v.GetType()))
{
// csv encode the value
case TypeCode.String:
string value = (string)v;
if (value.Contains(",") || value.Contains('"') || value.Contains("\n"))
{
value = value.Replace("\"", "\"\"");
if (value.Length > 31735)
{
value = value.Substring(0, 31732) + "...";
}
writer.Write("\"" + value + "\"");
}
else
{
writer.Write(value);
}
break;
default: writer.Write(v); break;
}
}
}
private static bool IsAnonymous(this Type type)
{
if (type == null)
throw new ArgumentNullException("type");
// HACK: The only way to detect anonymous types right now.
return Attribute.IsDefined(type, typeof(CompilerGeneratedAttribute), false)
&& type.IsGenericType && type.Name.Contains("AnonymousType")
&& (type.Name.StartsWith("<>") || type.Name.StartsWith("VB$"))
&& (type.Attributes & TypeAttributes.NotPublic) == TypeAttributes.NotPublic;
}