Question

I’ve got my code to delete rows out of the database when the user clicks on the Delete button in my GridView, but the GridView isn’t updating to reflect the new data changes.

Here’s my code:

    <asp:GridView runat="server" ID="grdQuestions" AutoGenerateColumns="false" Width="100%" CellSpacing="10"
         PagerSettings-Visible="true">
        <HeaderStyle CssClass="aspNetHeader" />
        <Columns>
            <asp:BoundField DataField="QuestionID" HeaderText="QID" />
            <asp:BoundField DataField="ModuleID" HeaderText="Mod #" />
            <asp:BoundField DataField="QuestionText" HeaderText="Question" />
            <asp:BoundField DataField="CorrectAnswer" HeaderText="Answer" />
            <asp:BoundField DataField="AnswerNote" HeaderText="Note" />
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:HyperLink runat="server" ID="lnkEdit" Text="Edit"></asp:HyperLink>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:LinkButton runat="server" ID="lnkDelete" Text="Delete" CommandArgument='<%# eval("QuestionID") %>'></asp:LinkButton>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

Protected Sub grdQuestions_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles grdQuestions.RowCommand
    If e.CommandName = "Delete" Then

        sql = "delete from tmp_Questions where QuestionID = " & e.CommandArgument
        Dim cmd As New SqlCommand(sql, d.SQLConnection)

        d.SQLConnection.Open()
        cmd.ExecuteNonQuery()
        d.SQLConnection.Close()

        GetModuleData()
    End If
End Sub

Protected Sub grdQuestions_RowDeleting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles grdQuestions.RowDeleting
    GetModuleData()
End Sub

Private Sub GetModuleData()
    ' ddlModules is a drop down where the user can select a module to filter questions by.
    Dim selid As Integer = ddlModules.SelectedItem.Value
    sql = "select QuestionID, ModuleID, LEFT(QuestionText, charindex(' ', QuestionText, 30)) as QuestionText, CorrectAnswer," & vbCrLf & _
        "AnswerNote from tmp_Questions" & vbCrLf & _
        "where ModuleID = " & selid & vbCrLf & _
        "order by ModuleID"
    Dim cmd As New SqlCommand(sql, d.SQLConnection)
    cmd.CommandText = sql

    QuestionAdapter.SelectCommand = cmd
    QuestionAdapter.Fill(QuestionData)

    If QuestionData.Tables(0).Rows.Count > 0 Then

        grdQuestions.DataSource = QuestionData
        grdQuestions.DataBind()
    End If
End Sub

Thanks in advance for having a look!

EDIT 1:
Did some stepping through the code and found that e.CommandArgument is not getting a value in grdQuestions_RowCommand

EDIT 1 (Revised):
The fact that e.CommandArgument wasn’t getting a value was my mistake. I’d changed the way it’s value was being assigned without removing the previous method.
The code runs through grdQuestions_RowCommand and then goes into grdQuestions_RowDeleting and then executes GetModuleData.
I have a feeling that to view changes to the grid, a PostBack might be required, but I’ve removed all DataBinding to an If Not IsPostBack Then block because the alternative caused problems with the DropDownList whose selection is used as a reference to populate the grid (ddlModules selected the Module whose Questions will display in the grid).

Answer 1

You have neither specified the CommandName="Edit" for lnkEdit nor CommandName="Delete" for lnkDelete.

I have a feeling that to view changes to the grid, a PostBack might be required

Of course, a postback must occur and the GridView must be databound to it’s DataSource again after you’ve deleted the record. But that postback has been already occured when the user clicked the delete-link and the grdQuestions_RowDeleting has been handled.
Debug and ensure that the record gets deleted and afterwards the GridView gets databound again.