Why can I not access this RadGrid Control

Question

I have a very simple Telerik RadGrid I am not using auto generate columns. I am using gridbound columns and creating my own. I have the edit mode set to Inplace. Here is the ASPX for the RAdGid

<div id="Grid">
                <telerik:RadGrid RenderMode="Lightweight" runat="server" ID="RadGrid1" AutoGenerateColumns="false" AllowPaging="true"
                    OnNeedDataSource="UserGrid_NeedDataSource" OnUpdateCommand="RadGrid1_UpdateCommand"
                    OnItemCreated="RadGrid1_ItemCreated" OnDeleteCommand="RadGrid1_DeleteCommand"
                    OnInsertCommand="RadGrid1_InsertCommand">
                    <MasterTableView DataKeyNames="UserID" CommandItemDisplay="Top" EditMode="InPlace">
                        <Columns>
                            <telerik:GridEditCommandColumn />
                            <telerik:GridBoundColumn DataField="UserID" HeaderText="User ID" ReadOnly="true"
                                ForceExtractValue="Always" ConvertEmptyStringToNull="true" />
                            <telerik:GridCheckBoxColumn DataField="Active" HeaderText="Active" SortExpression="Active" UniqueName="chkActive"></telerik:GridCheckBoxColumn>
                            <telerik:GridTemplateColumn HeaderText="Role">
                                <ItemTemplate>
                                    <%#DataBinder.Eval(Container.DataItem, "Role")%>
                                </ItemTemplate>
                                <EditItemTemplate>
                              <asp:DropDownList runat="server" ID="ddlRoles">
                                  <asp:ListItem Text ="Admin" Value ="Administrator"></asp:ListItem>
                                  <asp:ListItem Text ="User" Value ="User"></asp:ListItem>
                              </asp:DropDownList>
                          </EditItemTemplate>
                            </telerik:GridTemplateColumn>
                            <telerik:GridBoundColumn DataField="FirstName" HeaderText="First Name" UniqueName="FirstName" />
                            <telerik:GridButtonColumn ConfirmText="Delete this User?" ConfirmDialogType="RadWindow"
                                ConfirmTitle="Delete" ButtonType="FontIconButton" CommandName="Delete" />
                        </Columns>
                        <EditFormSettings InsertCaption="Add new item" CaptionFormatString="Edit User: {0}" CaptionDataField="FirstName">
                             <EditColumn FilterControlAltText="Filter EditCommandColumn column"></EditColumn>
                        </EditFormSettings>
                    </MasterTableView>
                    <PagerStyle Mode="NextPrevAndNumeric" />
                </telerik:RadGrid>
            </div>

I have removed several of the columns to shorten the code example. Below is a shortened e C# code

protected void RadGrid1_UpdateCommand(object sender, GridCommandEventArgs e)
    {
        GridEditableItem editedItem = e.Item as GridEditableItem;
        UserControl userControl = (UserControl)e.Item.FindControl(GridEditFormItem.EditFormUserControlID);
        string strUserID = editedItem.OwnerTableView.DataKeyValues[editedItem.ItemIndex]["UserID"].ToString();
        int intUserId = Convert.ToUInt16(strUserID);

        using (ExpungeEntities db = new ExpungeEntities())
        {

            var Results = db.USERS_T_DATA.SingleOrDefault(i => i.UserID == intUserId);
            if (Results == null)
            {
                RadGrid1.Controls.Add(new LiteralControl("Unable to locate that user for updating"));
                e.Canceled = true;
                return;
            }
            Results.Role = (userControl.FindControl("ddlRoles") as DropDownList).SelectedValue;
            Results.FirstName = (userControl.FindControl("FirstName") as TextBox).Text;

        }
    }

When I run the code I get this error message: {"Object reference not set to an instance of an object."}

It looks like I am not getting a reference to the control. Can anyone tell me what is happening here? I have used this method to get values from a RadGrid using a USerControl to edit or add records, this is the first time I have attempted to use the Inplace editing.

I was able to access the controls but had to eliminate the The Telerik GridBoundColumn and instead use the GridTemplateColumn, ItemTemplat and EidtItemTemplate. In the EditdItemTemplate I use an asp textbox.

I still have an issue, when I click the edit button the pop up form appears but none of the data is populated. Below is an example of my RadGrid Rows.

                                    <ItemTemplate>
                                    <asp:Label ID="lblFirstName" runat="server"
                                        Text='<%# DataBinder.Eval(Container.DataItem, "FirstName") %>'>
                                    </asp:Label>
                                </ItemTemplate>
                                <EditItemTemplate>
                                    <asp:TextBox ID="txtFirstName" runat="server"></asp:TextBox>
                                </EditItemTemplate>
                            </telerik:GridTemplateColumn>

And I access the controls with this C# code:

DropDownList ddl = (DropDownList)editableItem.FindControl("ddlRole") as 
DropDownList;
            d.Role = ddl.SelectedValue;
            CheckBox CheckBox1 = editableItem.FindControl("chkActive") as 
CheckBox;
            d.Active = CheckBox1.Checked;
            d.FirstName = (editableItem.FindControl("txtFirstName") as 
TextBox).Text.Trim();

on the Results.Role = (userControl.FindControl("ddlRoles") as DropDownList).SelectedValue; line — Perry

Alexandru Popa Alexandru Popa · Accepted Answer · 2018-04-20T19:35:15

From my experience with InPlace edit, you don't need any UserControl to access your edit controls. You can access them directly from GridEditableItem. Try to access your controls like this:

var ddlRoles = editedItem.FindControl("ddlRoles") as DropDownList;
if(ddlRoles != null)
{
    // use your drop down list
}

I tend to use inline temporary variables for safe casting. Here is how I would rewrite your code (if you use C# 7).

protected void RadGrid1_UpdateCommand(object sender, GridCommandEventArgs e)
{
    if (e.Item is GridEditableItem editedItem)
    {
        var strUserID = Convert.ToString(editedItem.OwnerTableView.DataKeyValues[editedItem.ItemIndex]["UserID"]);
        var intUserId = Convert.ToUInt16(strUserID);

        using (ExpungeEntities db = new ExpungeEntities())
        {
            var Results = db.USERS_T_DATA.SingleOrDefault(i => i.UserID == intUserId);
            if (Results == null)
            {
                RadGrid1.Controls.Add(new LiteralControl("Unable to locate that user for updating"));
                e.Canceled = true;
                return;
            }

            if (editedItem.FindControl("ddlRoles") is DropDownList ddlRoles)
                Results.Role = ddlRoles.SelectedValue;

            if (editedItem.FindControl("FirstName") is TextBox txtFirstName)
                Results.FirstName = txtFirstName.Text;    
        }
    }
}

Why can I not access this RadGrid Control

2 Answers