How can I convert an unmanaged IntPtr type to a c# string?

Benj picture Benj · Feb 7, 2012 · Viewed 29.8k times · Source

I'm new to C# (from a native C++ background) and I'm trying to write a little UI to print windows broadcast messages among other things. I've overridden the default WndProc message loop in my C# program like so:

[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")]
    protected override void WndProc(ref Message m)
    {
        // Listen for operating system broadcasts.
        switch (m.Msg)
        {
            case WM_SETTINGCHANGE:

                this.richTextLog.Text += "WM_SETTINGCHANGE - lParam=" + m.LParam.ToString() + "\n";

                break;
        }
        base.WndProc(ref m);
    }

What I'd like to know, is how to obtain a string representation of the lParam object which is of type IntPtr. It's essentially a void* in C++ land, can I cast it inside C# somehow? Presumably doing so is inherently unsafe.

Answer

GSerg picture GSerg · Feb 7, 2012

Marshal.PtrToStringAuto Method (IntPtr)

Allocates a managed String and copies all characters up to the first null character from a string stored in unmanaged memory into it.