主题：[求助]if……else后总被执行的代码问题？

1、

If e.DataCol.name ="文件序号" Then
    Dim dr As DataRow=e.DataRow
    If dr.Isnull("文号前缀") Then
        MessageBox.Show("文号前缀和文件年号不能为空值!", "提示")
        e.Cancel = True
    End If
    'Else
    Dim qz As String = e.DataRow("文号前缀")
    Dim nh As String = e.DataRow("年号")
    Dim xh As String = e.DataRow("文件序号")
    Dim wh As String = qz & "【" & nh & "】" & xh & "号"
    MessageBox.show(wh)
    Dim dr1 As DataRow = e.DataTable.Find("文号 = '" & wh & "'")
systemready = False
    If dr1 IsNot Nothing Then
        MessageBox.Show("此文号已经存在!")
        e.DataRow("文件序号") = Nothing
        e.Cancel = True
        'ElseIf dr Is Nothing Then
    Else
        e.DataRow("文号") = qz & "【" & nh & "】" & xh & "号"
        'e.DataRow("登记人") = _username
        'e.DataRow("登记时间") = Date.now
    End If
systemready = True
End If

2、

e.cancel = True
Forms("文件登记").Open()