请教高手DataGridView 修改数据报错了 也存不到数据库

用户信息的修改 点那个DataGridView应该显示到下面的文本框里 但是现在没有反应，还一个提示是什么数组越界  表中 4个字段 UserId UserName Password  Role
UserID 是只读的 但是有个文本框可以显示的  剩下的都可以改变 但是存不到数据库里
代码如下 拜谢高手了 ！

Private Sub DataGridView1_Click(sender As System.Object, e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
        Dim selRow As DataGridViewRow = DataGridView1.SelectedRows(0)//这行说什么数组越界了
        txtUserId.Text = selRow.Cells(0).Value.ToString()
        txtUserName.Text = selRow.Cells(0).Value.ToString()
        txtPassword.Text = selRow.Cells(2).Value.ToString()
        txtRole.Text = selRow.Cells(3).Value.ToString()
    End Sub  这个是点那个DataGridView
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Private Sub btnChange_Click(sender As System.Object, e As System.EventArgs) Handles btnChange.Click
        Dim row As DataRow = BindingContext(DataGridView1.DataSource, DataGridView1.DataMember).Current.Row //这行最后的Row 点不出来
        row("UserName") = txtUserName.Text
        row("Password") = txtPassword.Text
        row("Role") = txtRole.Text
        T_UserTableAdapter.Update(HotelDataSet.T_User)
        HotelDataSet.T_User.AcceptChanges()
    End Sub