Vb.net 有人知道这个问题的解决办法吗？

你还没有说明这个问题。但是，只要阅读代码，就可以使用count（），它将变量count作为函数调用。此外，计数从未定义。请尝试：

 Private Sub Btnlog_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnlog.Click
        If txtuser.Text = "Manish" And txtpw.Text = "Nair" Then
            MessageBox.Show("welcome")
        Else

            MessageBox.Show("Try again")
            count= count() + 1
            If count = 3 Then
                Me.Close()
            End If



        End If
    End Sub

     Private Sub Btnlog_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnlog.Click
            dim count as integer = 0 ' Define count

            If txtuser.Text = "Manish" And txtpw.Text = "Nair" Then
                MessageBox.Show("welcome")
            Else
                MessageBox.Show("Try again")
                count = count + 1

                If count = 3 Then
                    Me.Close()
                End If
            End If
        End Sub