C#

string string1 = "[Hi All]";
string1 = string1.Replace("[","").Replace("]","").Replace(" ","");

<br />
    Private Function CheckExistance(ByVal strFormname As String) As Boolean<br />
        'determine if the form already exists<br />
        Dim frmtest As Form<br />
        Dim blnFound As Boolean = False<br />
        'does form already Exists?<br />
        For Each frmtest In Me.MdiChildren<br />
            With frmtest<br />
                If .Name = strFormname Then<br />
                    .Activate() 'Activate Previous instance.<br />
                    blnFound = True<br />
<br />
<br />
                End If<br />
            End With<br />
        Next<br />
        Return blnFound<br />
<br />
    End Function<br />
<br />

<br />
     Dim blnFormExists As Boolean = False<br />
<br />
                blnFormExists = CheckExistance("Form1")<br />
                If Not blnFormExists Then<br />
                    Dim objform1 As New Form1<br />
                    With objform1 <br />
                        .MdiParent = Me<br />
                        .Show()<br />
                    End With<br />
                End If<br />

TV.Nodes.Add();