c# - if condition for MDI Parent Control -

i have mdi parent , mdi child , want know if condition should put call right class .

senario got button in mdi parent (selectall) want use button active mdi child .

lets say:

private void iselectall_itemclick(object sender,  e)         {             form dtexteditor = new dtexteditor();             //dtexteditor.show();              if (dtexteditor.mdichild == true)             {                     rtb.selectall();             }          } 

but error

operator == cannot applied operands of type 'system.windows.forms.form' , 'bool'

appears ... should do?

you need form.ismdichild check if form mdi child.

gets value indicating whether form multiple-document interface (mdi) child form.

private void iselectall_itemclick(object sender,  e) {     form dtexteditor = new dtexteditor();     //dtexteditor.show();      if (dtexteditor.ismdichild)     {             rtb.selectall();     }  } 

to check mdicontainer use form.ismdicontainer property