Question

我想从DataGridView的1行获取数据，我选择了我的文本框这是我的代码，

Private Sub DataGridView1_CurrentCellChanged(sender As Object, e As EventArgs) Handles DataGridView1.CurrentCellChanged

    Dim dColums(0) As DataColumn
    dColums(0) = dsetmember.Tables("member").Columns(0)
    dsetmember.Tables("member").PrimaryKey = dColums

    'MessageBox.Show(DataGridView1.CurrentRow.Index, 1)
    If DataGridView1.CurrentRow.Index = -1 Then
        txtNamaMember.Text = ""
        txtKodeMember.Text = ""
        txtNoHP.Text = ""
    Else
        Dim dr As DataRow = dsetmember.Tables("member").Rows.Find(DataGridView1.Item(DataGridView1.CurrentRow.Index, 0))
        txtKodeMember.Text = dr(0)
    End If

End Sub

我收到此错误，nullreferenceException was unhandled Object reference not set to an instance of an object.

thx b4。

Answer 1

错误发生在dr（0）到textbox.Text的转让中这意味着Find方法未找到传递的值，因此结果为NULL。当dr是Nothing时试图引用dr(0)就像写NOTHING（0），当然，这将失败

Dim dr As DataRow = dsetmember.Tables("member").Rows.Find(DataGridView1.Item(DataGridView1.CurrentRow.Index, 0))
if dr IsNot Nothing then
    txtKodeMember.Text = dr(0)
else
    MessageBox.Show("Value not found")
End If

还要记住，Find方法搜索在表的主键列上传递的值。您确定网格的第一列包含主键吗？

Answer 2

尝试更改此部分..

If DataGridView1.CurrentRow.Index = -1 Then
    txtNamaMember.Text = ""
    txtKodeMember.Text = ""
    txtNoHP.Text = ""
Else
    Dim dr As DataRow = dsetmember.Tables("member").Rows.Find(DataGridView1.Item(DataGridView1.CurrentRow.Index, 0))
    txtKodeMember.Text = dr.item(0)
End If

从vb.net 2012上的数据gridview获取行数据

2 个答案: