Call another interface button through win32API

Functional specifications

There are two independent teams created by two teams winform Interface , One of the teams, without knowing the source code , Operating the interface of another team button.

Exhibition

The main interface is as follows ：

The sub interface is as follows ：

The sub interface has a button （ test ）, Click this button , eject “ Prompt content of word form ” Prompt box .
When clicking on the parent form （Form1） Button on （button1） when , You can manipulate subforms （ The form of the subform ） The button （ test ）, And a prompt box appears

Code

Subform code ：

namespace TestForm
{
    public partial class MyTestForm : Form
    {
        public MyTestForm()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show(" Prompt contents of subform ！");
        }
    }
}

The code of the parent form

    public partial class Form1 : Form
    {
        [DllImport("user32.dll", EntryPoint = "FindWindowA", SetLastError = true)]
        private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", EntryPoint = "FindWindowEx", SetLastError = true)]
        private static extern IntPtr FindWindowEx(IntPtr hwndParent, uint hwndChildAfter, string lpszClass, string lpszWindow);

        [DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true, CharSet = CharSet.Auto)]
        private static extern int SendMessage(IntPtr hwnd, uint wMsg, int wParam, int lParam);

        [DllImport("user32.dll", EntryPoint = "SetForegroundWindow", SetLastError = true)]
        private static extern void SetForegroundWindow(IntPtr hwnd);  

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                //Process.Start("TestForm.exe");

                const int WM_CLICK = 0x00F5;// Mouse click message , Values of various messages , You can refer to MSDN 

                string lpszName_TestChild = " The form of the subform ";// The title of the subform （Text Property value ） 
                string lpszName_btnYes = " test ";// On subform button The title of the （Text Property value ） 

                IntPtr hwndTestChild = new IntPtr();// Handle to the subform  
                IntPtr hwndbtnYes = new IntPtr();// On subform button The handle of  

                hwndTestChild = FindWindow(null, lpszName_TestChild);// Get the handle of the subform  
                hwndbtnYes = FindWindowEx(hwndTestChild, 0, null, lpszName_btnYes);// Get on the subform button The handle of  

                if (hwndTestChild != IntPtr.Zero)
                {
                    SendMessage(hwndbtnYes, WM_CLICK, 0, 0);// On the subform button Send a mouse click message , 
                }
                else
                {
                    MessageBox.Show(" Not found ！");
                }


            }
            catch (System.Exception ex)
            {
                throw ex;
            }
        }


    }

Other instructions

1、 Method description ：

    [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
   private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

here EntryPoint = “FindWindow” or EntryPoint = “FindWindowA” All possible .
My environment VS2010,Win7 The flagship . Before FindWindow The return result of is always 0. But I don't know why .

2、 About session0 Related issues ：

1、 About the part WIN32 API stay WIN 7 Problem of lower failure
2、Session 0 Isolation
3、FindWindow Always return 0

3、 Reference material

Interprocess communication