That's a fun and useful little project. This worked well, I hope I got the chaining right. Drop a picturebox and a label on a form, then paste this code:
using System;
using System.Windows.Forms;
namespace WindowsApplication1 {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
this.FormClosing += Form1_Closing;
this.Load += Form1_Load;
}
private IntPtr mPrevViewer;
private void Form1_Load(object sender, EventArgs e) {
// Register notification
mPrevViewer = SetClipboardViewer(this.Handle);
updateClipboard();
}
private void Form1_Closing(object sender, FormClosingEventArgs e) {
// Remove notification
ChangeClipboardChain(this.Handle, mPrevViewer);
}
private void updateClipboard() {
// Called when clipboard contents changed
pictureBox1.Image = null;
label1.Text = "";
if (Clipboard.ContainsText()) label1.Text = Clipboard.GetText();
if (Clipboard.ContainsImage()) pictureBox1.Image = Clipboard.GetImage();
}
protected override void WndProc(ref Message m) {
if (m.Msg == WM_CHANGECBCHAIN) {
if (m.WParam == mPrevViewer) mPrevViewer = m.LParam;
else if (mPrevViewer != null) SendMessage(mPrevViewer, m.Msg, m.WParam, m.LParam);
}
else if (m.Msg == WM_DRAWCLIPBOARD) {
updateClipboard();
if (mPrevViewer != null) SendMessage(mPrevViewer, m.Msg, m.WParam, m.LParam);
}
base.WndProc(ref m);
}
// P/Invoke declarations
private static int WM_CHANGECBCHAIN = 0x30d;
private static int WM_DRAWCLIPBOARD = 0x308;
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern IntPtr SetClipboardViewer(IntPtr hWnd);
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern bool ChangeClipboardChain(IntPtr hRemove, IntPtr hNext);
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp);
}
}
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