嗨
试试这个:

Hi
try this:

frmTrnDialog objTrnDialog = new frmTrnDialog();
objTrnDialog.show(this);

将其用于子表格:

use this for child form:

frmMain frm = this.Owner as frmMain;

(form parent = frmMain)
关键是，构成您公开的孩子的组件
祝你好运，
阿米尔(Amir)

(form parent=frmMain)
The point is, the components that form the Child You''re Public
good luck,
Amir

http://social.msdn.microsoft.com/Forums/zh-CN/csharplanguage/thread/e0985e8a-bbc1-48bb-afc0-f965f797c92d/ [ http: //stackstackflow.com/questions/2356337/c-how-to-show-a-child-form-within-a-mdi-container-form-which-its-windowstate [使用C#引入MDI表单 [

http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/e0985e8a-bbc1-48bb-afc0-f965f797c92d/[^]
http://***.com/questions/2356337/c-how-to-show-a-child-form-within-a-mdi-container-form-which-its-windowstate[^]
Introduction to MDI Forms with C#[^]