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System Null Exception Error after adding CustomFilteringColumn in Project.

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Grid

This is a migrated thread and some comments may be shown as answers.

gc_0620 asked on 28 Oct 2011, 04:56 PM

Filter-Template-Column-Error.jpg

Using VS 2008 SP1 with RadControls for ASP.NET 2011.2.712.V 2.

I copied below example into my Project.

http://demos.telerik.com/aspnet-ajax/grid/examples/programming/filteringtemplatecolumns/defaultcs.aspx

After adding the FilteringTemplateColumns.cs in APP_Code folder, I am getting attached error message.

The results are OK except the error shows in Visual Studio Design/Split Mode. This error does not
show in Telerik Demo.

Below is complete Code:

<%@ Page Language="c#" AutoEventWireup="false" CodeFile="DefaultCS.aspx.cs" Inherits="Telerik.GridExamplesCSharp.Programming.FilteringTemplateColumns.DefaultCS" %>

<%@ Register TagPrefix="custom" Namespace="FilteringTemplateColumns" %>

<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

</head>

<body >

<form id="mainForm" method="post" runat="server">

<telerik:RadScriptManager ID="RadScriptManager1" runat="server" />

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">

<AjaxSettings>

<telerik:AjaxSetting AjaxControlID="RadGrid1">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="RadGrid1" />

</UpdatedControls>

</telerik:AjaxSetting>

</AjaxSettings>

</telerik:RadAjaxManager>

<telerik:RadGrid ID="RadGrid1" DataSourceID="SqlDataSource1" Width="97%" AllowFilteringByColumn="True"

AllowSorting="True" PageSize="12" ShowFooter="True" AllowPaging="True" runat="server"

AutoGenerateColumns="False" GridLines="None" ShowStatusBar="true">

<GroupingSettings CaseSensitive="false" />

<MasterTableView EditMode="InPlace" AllowFilteringByColumn="True" ShowFooter="True"

DataKeyNames="CustomerID" TableLayout="Auto">

<Columns>

<telerik:GridBoundColumn DataField="ContactName" HeaderText="Contact name">

<HeaderStyle Width="25%" />

</telerik:GridBoundColumn>

<telerik:GridBoundColumn DataField="ContactTitle" HeaderText="Contact title"

AutoPostBackOnFilter="true" CurrentFilterFunction="Contains" ShowFilterIcon="false">

<HeaderStyle Width="25%" />

</telerik:GridBoundColumn>

<telerik:GridTemplateColumn DataField="City" HeaderText="TemplateColumn City">

<HeaderStyle Width="25%" />

<ItemTemplate>

<%# Eval("City") %>

</ItemTemplate>

</telerik:GridTemplateColumn>

<custom:MyCustomFilteringColumn DataField="Country" FilterControlWidth="180px"

HeaderText="Custom TemplateColumn Country">

<headerstyle width="25%" />

<itemtemplate>

<img src='Img/<%# Eval("Country") %>.gif'

alt="" style="vertical-align:middle;margin-right:7px;"/><%# Eval("Country") %>

</itemtemplate>

</custom:MyCustomFilteringColumn>

</Columns>

</MasterTableView>

</telerik:RadGrid>

<br />

<asp:SqlDataSource ID="SqlDataSource1" ConnectionString="<%$ ConnectionStrings:NorthWindConnectionString %>"

ProviderName="System.Data.SqlClient" SelectCommand="SELECT CustomerID, ContactName, ContactTitle, Country, City FROM Customers"

runat="server"></asp:SqlDataSource>

</form>

</body>

</html>

DefaultCS.aspx.cs

_____________

using Telerik.Web.UI;

using System.Web.UI.WebControls;

namespace Telerik.GridExamplesCSharp.Programming.FilteringTemplateColumns

{

public partial class DefaultCS : System.Web.UI.Page

{

}

_________

FilteringTemplateColumns.cs

using Telerik.Web.UI;

using System.Data;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data.SqlClient;

using System.Configuration;

namespace FilteringTemplateColumns

{

public class MyCustomFilteringColumn : GridTemplateColumn

{

public DataTable GetDataTable(string queryString)

{

string ConnString = ConfigurationManager.ConnectionStrings["NorthWindConnectionString"].ConnectionString;

SqlConnection MySqlConnection = new SqlConnection(ConnString);

SqlDataAdapter MySqlDataAdapter = new SqlDataAdapter();

MySqlDataAdapter.SelectCommand = new SqlCommand(queryString, MySqlConnection);

DataTable myDataTable = new DataTable();

MySqlConnection.Open();

try

{

MySqlDataAdapter.Fill(myDataTable);

}

finally

{

MySqlConnection.Close();

}

return myDataTable;

}

protected override void SetupFilterControls(TableCell cell)

{

RadComboBox rcBox = new RadComboBox();

rcBox.ID = "DropDownList1";

//rcBox.Width = Unit.Percentage(100);

rcBox.AutoPostBack = true;

rcBox.DataTextField = this.DataField;

rcBox.DataValueField = this.DataField;

rcBox.SelectedIndexChanged += rcBox_SelectedIndexChanged;

DataTable table = GetDataTable(string.Format("SELECT DISTINCT {0} FROM {1}", this.DataField, "Customers"));

DataRow row = table.NewRow();

row[this.DataField] = "";

table.Rows.InsertAt(row, 0);

rcBox.DataSource = table;

cell.Controls.Add(rcBox);

}

protected override void SetCurrentFilterValueToControl(TableCell cell)

{

if (!(this.CurrentFilterValue == ""))

{

((RadComboBox)cell.Controls[0]).Items.FindItemByText(this.CurrentFilterValue).Selected = true;

}

protected override string GetCurrentFilterValueFromControl(TableCell cell)

{

string currentValue = ((RadComboBox)cell.Controls[0]).SelectedItem.Value;

this.CurrentFilterFunction = (currentValue != "")? GridKnownFunction.EqualTo : GridKnownFunction.NoFilter;

return currentValue;

}

private void rcBox_SelectedIndexChanged(object sender, Telerik.Web.UI.RadComboBoxSelectedIndexChangedEventArgs e)

{

((GridFilteringItem)(((RadComboBox)sender).Parent.Parent)).FireCommandEvent("Filter", new Pair());

}

Any help will be appreciated.

Thanks

GC_0620

System Null Exception Error after adding CustomFilteringColumn in Project.

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