RadGrid download attachment doesnt work inside Ajax panel

If your download button inside the RadGrid doesnt work if in an ajax panel:

 All you have to do is below( "btnDownload" is the id of the control
 which causes the download):

       function RequestStart(sender, args) {
            if (args.get_eventTarget().indexOf("btnDownload") >= 0) {
                args.set_enableAjax(false);
            }
        }

<telerik:RadAjaxPanel runat="server" LoadingPanelID="pnlLoading" 
ID="pnlMain" ClientEvents-OnRequestStart="RequestStart">
 

  <telerik:GridTemplateColumn HeaderText="Business Card" >
      <ItemTemplate>
    <asp:LinkButton runat="server" ID="btnDownload" Text="Download" 
CommandName="Download" CommandArgument='<%#Eval("ID") %>'    >
    </asp:LinkButton>
       </ItemTemplate>
 </telerik:GridTemplateColumn>

Radajaxpanel and RegisterStartupScript

If you want call javascript from server side while using RadAjaxPanel use 
ResponseScripts.Add method. 

//Doesnt work  :
   ScriptManager.RegisterStartupScript(this, GetType(), "RefreshDD", 
"RefreshDD();", true); 

//Works :
   pnlMain.ResponseScripts.Add("RefreshDD();"); 

Use Eval to run javascript method inside item template of radgrid

This works :
                <telerik:GridTemplateColumn HeaderText="Edit">
                        <ItemTemplate>
                            <asp:Button runat="server" Text="Edit" AutoPostBack="False"
 OnClientClick='<%# String.Format("openAddContact({0})",Eval("ID"))%> '></asp:Button>

                        </ItemTemplate>
                    </telerik:GridTemplateColumn>

This doesn't:
                <telerik:GridTemplateColumn HeaderText="Edit">
                        <ItemTemplate>                        
     <telerik:RadButton ID="Button1" runat="server" Text="Edit" 

 AutoPostBack="False" 

 OnClientClicked='<%# String.Format("openAddContact({0})",Eval("ID"))%> '>
            </telerik:RadButton>
                        </ItemTemplate>
                    </telerik:GridTemplateColumn>

intersting hah 

Fix to RadNumericTextBox declarative binding error "Specified cast is not valid"

 <telerik:GridTemplateColumn HeaderText="No of  Subscribers">
          <ItemTemplate>
               <%#Eval("SentToCount") %>
          </ItemTemplate>
          <EditItemTemplate>
              <telerik:RadNumericTextBox ID="rnSentCount" runat="server" MaxValue="1000000"
CausesValidation="True"   NumberFormat-DecimalDigits="0" DataType="Int32"  MinValue="1" 
DbValue='<%#Bind("SentToCount") %>'/>
          </EditItemTemplate>
          <InsertItemTemplate>
              <telerik:RadNumericTextBox ID="rnSentCount" runat="server" MaxValue="1000000"
CausesValidation="True" NumberFormat-DecimalDigits="0" DataType="Int32"  MinValue="1"
DbValue='<%#Bind("SentToCount") %>'/>
           </InsertItemTemplate>
 </telerik:GridTemplateColumn>

  <%#Bind ()%> will not work with Value property so use DbValue instead and it will
 work like a charm. Why intellisense doesnt display DbValue : good question ... to telerik :) 

Using empty value in a databound GridDropDownColumn

 In RadGrid if you want to use dropdown box (or the ComboBox) then  there is this  GridDropDownColumn.
And if you want to databind it just set the datasource .
Then the question comes to how to add the empty item to the dropdown
For ex you want 3 items in the combo and "--None--" as the default item in the dropdown box
And if "--None--" is selected it should return null as value.
The EmptyListItemValue  property comes to help, set these 3 properties as below 

EmptyListItemText="None" EmptyListItemValue="" EnableEmptyListItem="True"

 <telerik:GridDropDownColumn HeaderText="TargetOrganisation" 
ListValueField="ID" UniqueName="TargetOrganisationID" 
 DataField="TargetOrganisationID" 
ListTextField="Alias" DataSouceID="edsOrganisation"EmptyListItemText="None" EmptyListItemValue="" EnableEmptyListItem="True">
</telerik:GridDropDownColumn>

RadGrid Getting Datakey value of selected row's

GeneralHelper.DeleteContact((int)((GridDataItem)e.Item).GetDataKeyValue("ID"));