Operator '=' is not defined for type 'DBNull' and string "1" ?

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how to fix?

This is my code:

VB

Dim x As Integer = 0
        While x <> DGVtry.RowCount
            If dgvtry.Rows(0).Cells(1).Value = "1" Then
                LBLq1.Text = dgvtry.Rows(x).Cells(0).Value
            ElseIf dgvtry.Rows(0).Cells(1).Value = "2" Then
                LBLq2.Text = dgvtry.Rows(0).Cells(0).Value
            End If
            x = x + 1
        End While

This is my table:

VB

id    counter
101      1
104      2
105      3
107      4

Thanks in advance!

Posted 5-Jun-14 21:27pm

charliedev

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3 solutions

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CPallini · Answer 1 · 2014-06-05T21:44:00

Solution 1

Well, the error message is pretty clear and you have to correctly handle null values (depending on your requirements you may either generate an error message or simply skip them).

Posted 5-Jun-14 21:44pm

CPallini

DamithSL · Answer 2 · 2014-06-05T21:51:00

Solution 2

you can do as below

VB

If NOT IsDbNull(dgvtry.Rows(0).Cells(1)) AndAlso dgvtry.Rows(0).Cells(1) = "1" Then

Posted 5-Jun-14 21:51pm

DamithSL

Nayan Rudani · Answer 3 · 2014-06-05T23:22:00

VB

 While x <> DGVtry.RowCount
    If Not IsDBNull(dgvtry.Rows(0).Cells(1)) Then

        If dgvtry.Rows(0).Cells(1).Value = "1" Then
            LBLq1.Text = dgvtry.Rows(x).Cells(0).Value
        ElseIf dgvtry.Rows(0).Cells(1).Value = "2" Then
            LBLq2.Text = dgvtry.Rows(0).Cells(0).Value
        End If

    End If
    x = x + 1
End While