容器内的VB.Net DataGridView不起作用

Question

I have the code below in VB.Net; tested for the 4 cases listed here:

1-This code Works; If I make the DataGridView1 variable outside "TabControl1";
2-This code NOT Works; If I make the DataGridView1 variable inside "TabControl1";
3-This code Works; If I make the DataGridView1 fixed outside "TabControl1";
4-This code Works; If I make the DataGridView1 fixed inside "TabControl1";

My Question is: How to make it work for case 2 (ie DataGridView1 variable inside "TabControl1")?

    Dim CurrentTable As String = "AAAA|BBBBB|CCCCC"
    Dim Values() As String = CurrentTable.Split("|"c)
    Dim DGV As DataGridView ' VARIABLE
    DGV = CType(Me.Controls("DataGridView1"), DataGridView) ' VARIABLE
    DGV.Rows.Add(Split(CurrentTable, "|")) ' VARIABLE
    DataGridView1.Rows.Add(Split(CurrentTable, "|")) ' FIXED

Answer 1

As explained in a comment, Me.Controls will only contain controls owned by the form. Controls which are in other container controls ( GroupBox , Panel , TabPage ) will reside in that control's ControlCollection .

You can use Find to also search those other containers:

' TRUE indicates you also want to search child containers
Dim dgvs = Me.Controls.Find("DataGridView1", True)
Dim myDGV As DataGridView
' dgvs will be an array of matching controls, so check
If dgvs.Count > 0 Then
    myDGV = CType(dgvs(0), DataGridView)
End If

If you know the name and/or will be referencing it often, it is simpler to declare a variable for it rather than go searching for the same control over and over:

Public Class Form123
   ' form level var:
   Private myDGV As DataGridView

  Private Form_Load(...
     ' set the reference:
     myDGV = DataGridView1