Cannot convert type 'System.Web.UI.Control' to 'System.Web.UI.UserControl

Question

My code is this ![enter image description here][1]

But I am getting a Null exception error :(

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim textquestionselected As New List(Of Integer)
        Dim imagequestionselected As New List(Of Integer)
        Dim text_question_id As Integer
        Dim image_question_id As Integer
        For Each gridviewrow As GridViewRow In GridView1.Rows
            If (CType(gridviewrow.FindControl("CheckBox1"), CheckBox).Checked) Then

                text_question_id = Convert.ToInt16(CType(gridviewrow.FindControl("small_int_question_id"), Label).Text)
                textquestionselected.Add(text_question_id)
            End If
        Next
        For Each gridviewrow1 As GridViewRow In GridView2.Rows
            If (CType(gridviewrow1.FindControl("CheckBox2"), CheckBox).Checked) Then

                image_question_id = CType(gridviewrow1.FindControl("small_int_question_id"), Label).Text
                imagequestionselected.Add(image_question_id)
            End If
        Next

enter image description here

I used bound Field instead Label .. but same error

When you have code, please copy/paste it into your answer as actual text, don't embed it as an image. You can search text within an image, images are on different domains and can be blocked, and it's hard to re-use your code in an answer. — mason
– mason, Commented Oct 31, 2014 at 20:38

Brian Mains · Accepted Answer · 2014-10-31 20:41:59Z

1

You have to check the type of row it is; it's probably the header or footer row. Check the RowType property to make sure it's a DataRow.

if (row.RowType == DataControlRowType.DataRow)
{
   //Check control 
}

Also according to your subject, make sure the type you are converting is the same. It would really help to see a snippet of the markup.

answered Oct 31, 2014 at 20:41

Brian Mains

50.8k35 gold badges155 silver badges260 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Aniket Over a year ago

I think the error is in 'Label' keyword in this line .. Convert.ToInt16(CType(gridviewrow.FindControl("small_int_question_id"), Label).Text)

Brian Mains Over a year ago

Right but without checking the type of row it is, you could be trying to find it in the header row, which doesn't exist. Also try using gridviewrow.Cells[index].FindControl to see if that makes a difference.

Collectives™ on Stack Overflow

Cannot convert type 'System.Web.UI.Control' to 'System.Web.UI.UserControl

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related