Allow null in GridDropDownColumn inside Radgrid

[Derek]

Is there a way to use the GridDropDownColumn and not require a value?

We have a grid that we want to use for editing, but several of the dropdowns don't require a value. If we use the default behaviour, the first entry in the list is automatically selected and saved. We've experimented with including a null value in the datasource, but this generates various errors.

Is there a simple way to use the dropdown behaviour without requiring a value to be selected?

[Rosen]

Hi Derek,

In order to add an empty item to RadGrid's DropDownColumn you should set EnableEmptyListItem to true and set EmptyListItemText and EmptyListItemValue appropriately.

All the best,
Rosen
the Telerik team

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[Alex Vr]

Hello Derek,

I'm trying to use GridDropDownColumn with null values.
I have set the properties to: EnableEmptyListItem="true" EmptyListItemText="NA" EmptyListItemValue="1"
But the problem is when I try to edit some row it throws JavaScript error:
Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: Editor cannot be initialized for column: BadLeadReasonID

How can I resolve the issue?

Best Regards,
Alex Vr

[Veli]

Hi Alex Vr,

You are getting a server error. If you disable all AJAX on your page, you will get exception info along with the stack trace that can tell you more about what caused the issue. If the problem persists, send us the stack trace along with your RadGrid definition and related code.

Greetings,
Veli
the Telerik team

[Alex Vr]

Hello Veli,

I couldn't recreate the problem but I solved it in little different way.
When the properties:EnableEmptyListItem="true" EmptyListItemText="NA" EmptyListItemValue="1" where set I had a problem that when I edit the the row and value was null it didn't select automatically the 'NA' in the combobox.
So I removed all the above properties and only left the ConvertEmptyStringToNull="true" property.
Aslo I added the following code the the events:

protected void LeadsRadGrid_ItemDataBound(object sender, Telerik.Web.UI.GridItemEventArgs e)
{
     .....

      if (e.Item is GridEditableItem && e.Item.IsInEditMode)
      {
            GridEditableItem editedItem = e.Item as GridEditableItem;
            ExtraLeadsCL.Database.Lead lead = (ExtraLeadsCL.Database.Lead)e.Item.DataItem;

            GridEditManager editMan = editedItem.EditManager;
            GridDropDownListColumnEditor editor = editMan.GetColumnEditor("BadLeadReasonID") as GridDropDownListColumnEditor;
            //editor.ComboBoxControl.Items.Clear();

            editor.ComboBoxControl.DataSource = ExtraLeadsCL.Core.BadLeadReason.GetAllBadLeadReasonsDatasource();
            editor.ComboBoxControl.DataTextField = "Title";
            editor.ComboBoxControl.DataValueField = "BadLeadReasonID";
            editor.ComboBoxControl.DataBind();

            editor.ComboBoxControl.Items.Add(new RadComboBoxItem("NA", "0"));

            if (lead.BadLeadReasonID == null)
                editor.ComboBoxControl.SelectedValue = "0";
            else
                editor.ComboBoxControl.SelectedValue = lead.BadLeadReasonID.ToString();
        }
}

Best Regards,
Alex Vr.