Is it possible to get result of Linq query after data binding a control.
Example below:
GridView.DataSource = From c in Customers
GridView.DataBind()
I tried to get GridView.DataSource in the GridView's DataBound event but that contains the Database Query not the actual result.
How can I get the result?
Use this but adapt to your requirements...
Dim queryResults = (From c in dc.Customers).ToList
Gridview.Datasource = queryResults
Gridview.DataBind()
i'm using grid control in DevExpress reports when i set data source dynamically to my grid control its not showing a output, anyone please help me to get.
this is my code
DataTable dtJobOrder = new DataTable();
string DTQuery = #"Select Product from JobOrder";
dtJobOrder = Generic.GetDataTable(DTQuery);
grdspare.DataSource = dtJobOrder;
Probably you already found a way.
You can achieve this by calling PopulateColumns method on grid view.
When you are dynamically set the data source to gridview then you have to set AutoGeneratedColumns to true.
AutoGeneratedColumns = true
I cannot find a complete example. Found tons on grid and combobox, but not textbox. This test is to lookup a “PhoneTypeName” from a UserPhoneType table with TypeCode = “0” and assign that first value to a asp.net textbox.
Currently, I am getting “Object reference not set to an instance of an object” when setting the text box to "phonetype.FirstOrDefault.PhoneTypeName.ToString"
Using dbContext As New EntitiesModel()
Dim phonetype As IEnumerable(Of User_PhoneType) = dbContext.User_PhoneTypes.Where(Function(c) c.PhoneTypeCode = "O")
mytextbox.Text = phonetype.FirstOrDefault.PhoneTypeName.ToString
End Using
----EDIT----
I changed as suggested. I ALSO successfully bound the entire list of PhoneTypes to a droplist control...to confirm the data is accessible. It must be the way I am going about querying the table for a single record here.
I get the same error, but at "Dim type = phonetype.First..."
The record is in the table, but it does not appear to be extracted with my code.
Dim phonetype As IEnumerable(Of User_PhoneType) = dbContext1.User_PhoneTypes.Where(Function(c) c.PhoneTypeCode = "M")
Dim type = phonetype.FirstOrDefault
If Object.ReferenceEquals(type, Nothing) = False And Object.ReferenceEquals(type.PhoneTypeName, Nothing) = False Then
mytextbox.Text = type.PhoneTypeName.ToString
End If
In general there are the following two possible reasons for getting this exception:
1) The phonetype list is empty and the FirstOrDefault method is returning a Nothing value.
2) The PhoneTypeName property of the first element of the phonetype list has a Nothing value.
In order to make sure that you will not get the Object reference not set to an instance of an object exception I suggest you add a check for Nothing before setting the TextBox value. It could be similar to the one below:
Dim type = phonetype.FirstOrDefault
If Object.ReferenceEquals(type, Nothing) = False And Object.ReferenceEquals(type.PhoneTypeName, Nothing) = False Then
mytextbox.Text = type.PhoneTypeName.ToString
End If
Fixed it.
I was able to view the SQL string being generated by using this:
mytextbox.text = phonetype.tostring
I saw that the SQL contained "NULL= 'O'"
I did it like the example?!? However, when I added .ToString to the field being queried, it worked.
So the final looks like this:
Using dbContext As New EntitiesModel()
Dim phonetype As IEnumerable(Of User_PhoneType) = dbContext.User_PhoneTypes.Where(Function(c) c.PhoneTypeCode.**ToString** = "O")
mytextbox.Text = phonetype.FirstOrDefault.PhoneTypeName.ToString
End Using
BTW, Dimitar point to check for null first is good advice (+1). The value was nothing as he said.
I'm creating a runtime dataset in page load. In this dataset I'm adding columns like that:
CrystalDecisions.CrystalReports.Engine.ReportDocument orpt =
new CrystalDecisions.CrystalReports.Engine.ReportDocument();
DataTable table = new DataTable("DataSet1");
table.Columns.Add("Fname", typeof(System.String));
table.Columns.Add("Lname", typeof(System.String));
table.Columns.Add("Salary", typeof(System.String));
DataRow row = table.NewRow();
row["Fname"] = "Mathew";
row["Lname"] = "Hayden";
row["Salary"] = "5000$";
table.Rows.Add(row);
ds.Tables.Add(table);
orpt.Load(MapPath("CrystalReport3.rpt"));
orpt.SetDataSource(ds.Tables[0]);
CrystalReportViewer1.ReportSource = orpt;
Records are not displayed in CrystalReport3.rpt when I'm going to run the program.
Please tell me how to set these coloums in Crystal Reports 3!
What happens if you move your code from the Page_Load to the Page_Init event handler of the ASP.NET page?
Try to set the AutoDataBind property to "true":
Gets or sets whether automatic data
binding to a report source is used. If
the value is set to True, the
DataBind() method is called after
OnInit() or Page_Init() events.
Another tip: did you try to call the RefreshReport() (or Refresh() in older versions) method of your CrystalReportViewer1 object?
Instead of
orpt.SetDataSource(ds.Tables[0]);
Do
orpt.SetDataSource(ds.Tables["table_name"]);
table_name is the table name you gave for the table
"Both DataSource and DataSourceID are defined on 'grdCommunication'. Remove one definition."
I just got this error today, the code has been working until this afternoon I published the latest version to our server and it broke with that error both locally and on the server. I don't use "DataSourceID", the application reads database queries into a datatable and sets the datatable as the DataSource on the GridViews. I did a search in Visual Studio, searching the entire solution and the string "DataSourceID" does not appear in even 1 line of code in the entire solution. This is the first thing that freaked me out.
I figure it had been working yesterday, so I reverted the code to yesterday's build. The error was still there. I kept going back a build, and still the issue is there. I went back a month, I am still getting the same error. This application was working fine this morning? There has really been no code changes, and no where in the application is the DataSourceID EVER set on any of the gridviews. Has anyone ever seen anything like this at all??
How can I get that error if DataSourceID is never set... and the word "DataSourceID" is not in my solution? I just did a wingrep on the entire tree doing a case insensitive search on datasourceid.... pulled up absolutely nothing. That word is absolutely no where in the entire application.
<asp:GridView ID="grdCommunication" runat="server"
Height="130px" Width="100%"
AllowPaging="true" >
... standard grid view column setup here...
</asp:GridView>
// Code behind.. to set the datasource
DataSet dsActivity = objCompany.GetActivityDetails();
grdCommunication.DataSource = dsActivity;
grdCommunication.DataBind();
// Updated: removed some confusing notes.
Try this:
DataSet dsActivity = objCompany.GetActivityDetails();
grdCommunication.DataSource = dsActivity.Tables[0];
grdCommunication.DataBind();
Holy smoke batman. The Table name was changed causing my Datasource to be no good. But that error message doesn't make any sense in this situation. So technically tsilb's solution will work if I call the table by index instead of by name, so I'll mark his solution as correct.
After reading his post, I tried dsActivity.Tables["Activities"] instead of passing the dataset to the Datasource and the table name to the Datamember, and obviously that didn't work, but If I pass the actual index, which I don't like doing because that index might change, then it is now working. But the messed up part, was that error.. That error was completely off base as to what the problem was. saying that I defined both and to remove one, when in reality, that was not the case. and another really messed up thing, was the table name was only changed to be all upper case... But hey, "Activities" is a different key than "ACTIVITIES".
Replace this code before this grdCommunication.DataSource = dsActivity;
grdCommunication.DataBind();
grdCommunication.DataSourceID="";
tslib is right, don't do:
grdCommunication.DataSourceID = null;
or the string.Empty version. You only use the DataSourceID if you're using a SqlDataSource or ObjectDataSource control for your binding.
It's called "declarative" binding because you're using "declared" controls from on your page. Binding to controls does not require a call to the DataBind() method.
Because you're DataBinding manually (calling grd.DataBind()) you only set the DataSourrce and then call DataBind().
I ran into the same error, but a totally different problem and solution. In my case, I'm using LINQ to SQL to populate some dropdown lists, then caching the results for further page views. Everything would load fine with a clear cache, and then would error out on subsequent page views.
if (Cache["countries"] != null)
{
lbCountries.Items.Clear();
lbCountries.DataValueField = "Code";
lbCountries.DataTextField = "Name";
lbCountries.DataSource = (Cache["countries"]);
lbCountries.DataBind();}
else
{
var lstCountries = from Countries in db_read.Countries orderby Countries.Name select Countries;
lbCountries.Items.Clear();
lbCountries.DataValueField = "Code";
lbCountries.DataTextField = "Name";
lbCountries.DataSource = lstCountries.ToList();
lbCountries.DataBind();
Cache.Add("countries", lstCountries, null, System.Web.Caching.Cache.NoAbsoluteExpiration, new TimeSpan(0, 240, 0), System.Web.Caching.CacheItemPriority.High, null);
}
The issue came from:
Cache.Add("countries", lstCountries, null, System.Web.Caching.Cache.NoAbsoluteExpiration, new TimeSpan(0, 240, 0), System.Web.Caching.CacheItemPriority.High, null);
When it should have been:
Cache.Add("countries", lstCountries.ToList(), null, System.Web.Caching.Cache.NoAbsoluteExpiration, new TimeSpan(0, 240, 0), System.Web.Caching.CacheItemPriority.High, null);
I got this error today, turns out that it had nothing to do with DataSourceID, and had everything to do with the DatasSource itself.
I had a problem in my DatasSource , and instead of getting a DatasSource related error, I got this meaningless error.
Make sure you're DatasSource is good, and this error should go away.
always bind dataset with table index to gridview...
ex. gridgrdCommunication.Table[0]; as metioned above by Tsilb
second way you intentionally write..
gridgrdCommunication.DataSourceID = String.Empty;
gridgrdCommunication.DataSource=ds;
gridgrdCommunication.DataBind();
Check you database structure.... if you are acceding your data throw a dbml file, the table structure in your database it's different of the dbml file structure
If you are using the Object Data Source and want to conditionally reload the grid in code behind you can successfully do this:
Dim datatable As DataTable = dataset.Tables(0)
Dim dataSourceID As String = gvImageFiles.DataSourceID
gvImageFiles.DataSourceID = Nothing
gvImageFiles.DataSource = datatable.DefaultView
gvImageFiles.DataBind()
gvImageFiles.DataSource = Nothing
gvImageFiles.DataSourceID = dataSourceID
You need to chose one way to bind the grid
if it is from code behind means using c# code then remove the datasourceid property from grid view from design view of grid
like this
//you have to make it like this
Please try this:
gvCustomerInvoiceList.DataSourceID = "";
gvCustomerInvoiceList.DataSource = ci_data;
gvCustomerInvoiceList.DataBind();
I got this error today. It turns out that my stored procedure did not return neither any record nor a structure. This was because I had an empty try catch without a raiserror.
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Page.DataBind()
End Sub
Function GetData()
Dim dt As New DataTable
Try
dt.Columns.Add("ROOM_ID", GetType(String))
dt.Columns.Add("SCHED_ID", GetType(String))
dt.Columns.Add("TIME_START", GetType(Date))
dt.Columns.Add("TIME_END", GetType(Date))
Dim dr As DataRow = dt.NewRow
dr("ROOM_ID") = "Indocin"
dr("SCHED_ID") = "David"
dr("TIME_START") = "2018-01-03 09:00:00.000"
dr("TIME_END") = "2018-01-03 12:00:00.000"
dt.Rows.Add(dr)
Catch ex As Exception
MsgBox(ex.ToString)
End Try
Return dt
End Function
and add this to your item DataSource="<%# GetData() %>"
In my case the connection string to the database was not working. Fixing the connection string got rid of this error.