Error in C# winform while show a new form

Question

Hi all am developing a C# Winform Application .Am using the MDI form in my application also i placed a Tab Control in MDI main form .When i tried to show a new form as a MDIchildBut it not showing . private void mnuForm1_Click(object sender EventArgs e) { Form1 frm1= new Form1(); frm1.MdiParent = this; frm1.Show(); } am getting the A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll  Error in output window. If i delete that Tab control form MDI then its working ... Here What's wrong with adding TabControl in MDIform. Thanks in Advance..

Prem Anandh Natchatran · Answer

Thanks to all no effect of using if (this.ActiveMdiChild != null) ActiveMdiChild.Close(); because i used one tabControl1 in MDI form It only hiding my childWindow #Dharam tried tabControl1.SendToBack(); tabControl1.BringToFront(); But it completly hiding tabControl1... #Ranjit Powar so I solved this by showing from as dialog box. Form1 frmobj = new Form1(); frmobj.ShowDialog(); here the only drawback is can't use new Form as child of MDI

Dharam Rai · Answer

@ Prem try this here I am attaching screen shot: Now double click ClassWise Subject (Child Menu) and you will be directed to the click event of the Menu Strip of the child menu here write the following code screen shot below: @Prem now go to your MDI for run and click the child menu you just set. Let me know

Ranjit Powar · Answer

Hey call tabControl1.SendToBack(); method while opening the child form. When you close the form again call tabControl1.BringToFront();

Prem Anandh Natchatran · Answer

Dharma I tried that but not working Here by i attached the screenshot in above the new form is hided by tab control cant bring in front by using form1.BringToFront();

Dharam Rai · Answer

@Prem do you badly want to use TabControl? or else you can get it done from MenuStrip in your MDI form. here: Double click your menu in MenuStrip in your MDI form and paste this code: if (this.ActiveMdiChild != null) { this.ActiveMdiChild.Close(); } Form1 em = new Form1 (); em.MdiParent = this; em.Show(); Now go to your Form1 and in Form1_Load (Load event) paste this code: Left = (MdiParent.ClientRectangle.Width - Width) / 2; Top = (MdiParent.ClientRectangle.Height - Height) / 2;