Windows Forms - Pass values from Form to user control

Question

I have user control that includes OpenFileDialog and PictureBox. I use it in editable forms where the user is allowed to select and save image along with the other info. The problem that I met is that I need to set openFileDialog.Filter and this Filter is actually the value of one my TextBox which is named txtCode.

Now I pass the txtCode.Text on the Form_load event but this is not good enough I need to get the value form the TextBox when the user tries to open the File Dialog. Because I use it as an User Control :

And thus I can't catch the button click event. In fact I can only handle the user control click event, which is fired when I click anywhere outside the File Browse button and the PictureBox which ruins my workaround plan to handle the event and check if the sender is a Button.

How can I pass the txtCode.Text value when the OpenFileDialog is opened or at least at a very close moment so I can work with the most current value?

Answer 1

Start a background thread just before opening the OpenFIleDialog. In the background thread, search for available open file dialog box and set the value of filename. you can also click the open button automatically also. There are windows API to do this that can be used in .net.

Sample for FindWindow:

**Calling Code:**

Thread thread2 = new Thread(new ThreadStart(MyClass.SelectFile));
thread2.IsBackground = true;
thread = thread2;
thread.Start();


**Class Code:**

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

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

[DllImport("user32.dll", CharSet=CharSet.Auto, SetLastError=true)]
private static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string lclassName, string windowTitle);

public void SelectFile(string filename)
{
    Thread.Sleep(0x3e8);
    IntPtr zero = IntPtr.Zero;
    IntPtr parentHandle = IntPtr.Zero;
    IntPtr child = new WinAPI(Process.GetCurrentProcess().MainWindowHandle, "#32770").GetChild();
    while (child == IntPtr.Zero)
    {
        Application.DoEvents();
    }
    if (child != IntPtr.Zero)
    {
        zero = child;
        parentHandle = FindWindowEx(zero, IntPtr.Zero, "ComboBoxEx32", "");
        if (parentHandle != IntPtr.Zero)
        {
            parentHandle = FindWindowEx(parentHandle, IntPtr.Zero, "ComboBox", "");
            if (parentHandle != IntPtr.Zero)
            {
                parentHandle = FindWindowEx(parentHandle, IntPtr.Zero, "Edit", "");
                if (parentHandle != IntPtr.Zero)
                {
                    SendMessage(parentHandle, 12, IntPtr.Zero, fileName);
                    parentHandle = FindWindowEx(zero, IntPtr.Zero, "Button", "&Open");
                    if (!(parentHandle == IntPtr.Zero))
                    {
                        SendMessage(parentHandle, 0xf5, IntPtr.Zero, "");
                    }
                }
            }
        }
    }
    Thread.Sleep(0x7d0);
}

Answer 2

You can use txtCode.Text anywhere in your form. Not only in your Form_Load handler. Just try using it where you need it.