CODEWITHSUNDEEP
c#winforms.net-2.0
yonan2236
yonan2236

Reputation: 13649

Open Notepad and add Text not working

I just saw this snippet from the internet but it doesn't work from me. It's suppose to open a new notepad application and add "asdf" into it.

Is there any wrong on the code?

[DllImport("User32.dll")]     
        public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, [MarshalAs(UnmanagedType.LPStr)] string lParam);

void Test()
{
         const int WM_SETTEXT = 0x000C;

    ProcessStartInfo startInfo = new ProcessStartInfo("notepad.exe");
    startInfo.UseShellExecute = false;
    Process notepad = System.Diagnostics.Process.Start(startInfo);
    SendMessage(notepad.MainWindowHandle, WM_SETTEXT, 0, "asdf");
}

Upvotes: 1

Views: 4815

Answers (3)

Anton Kedrov
Anton Kedrov

Reputation: 1767

To make sure that process is ready to accept input, call notepad.WaitForInputIdle(). And it is important to use MainWindowHandle of the process that was just created, not the any notepad process.

[DllImport("user32.dll")]
public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

[DllImport("User32.dll")]
public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);

static void ExportToNotepad(string text)
{
    ProcessStartInfo startInfo = new ProcessStartInfo("notepad");
    startInfo.UseShellExecute = false;

    Process notepad = Process.Start(startInfo);
    notepad.WaitForInputIdle();

    IntPtr child = FindWindowEx(notepad.MainWindowHandle, new IntPtr(0), null, null);
    SendMessage(child, 0x000c, 0, text);
}

Upvotes: 4

KF2
KF2

Reputation: 10153

try this:

    [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
    public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
    [DllImport("User32.dll")]
    public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);
        void Test()
        {
            ProcessStartInfo startInfo = new ProcessStartInfo("notepad.exe");
            startInfo.UseShellExecute = false;
            Process notepad = System.Diagnostics.Process.Start(startInfo);
            //Wait Until Notpad Opened
            Thread.Sleep(100);
            Process[] notepads = Process.GetProcessesByName("notepad");
            IntPtr child = FindWindowEx(notepads[0].MainWindowHandle, new IntPtr(0), "Edit", null);
            SendMessage(child, 0x000c, 0, "test");
        }

Upvotes: 0

Rajesh Subramanian
Rajesh Subramanian

Reputation: 6490

Following Code will do the trick for you,

[DllImport("user32.dll", EntryPoint = "FindWindowEx")]
    public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
    [DllImport("User32.dll")]
    public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);
    private void button1_Click(object sender, EventArgs e)
    {
        Process [] notepads=Process.GetProcessesByName("notepad");
        if(notepads.Length==0)return;            
        if (notepads[0] != null)
        {
            IntPtr child= FindWindowEx(notepads[0].MainWindowHandle, new IntPtr(0), "Edit", null);
            SendMessage(child, 0x000C, 0, textBox1.Text);
        }
    }

Upvotes: 0

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