C# member cannot be accessed with an instance reference

Question

So i have these variables

List<string> files, images = new List<string>();
string rootStr;

And this threaded function

private static int[] thread_search(string root,List<string> files, List<string> images)

But when I try to start the thread:

trd = new Thread(new ThreadStart(this.thread_search(rootStr,files,images)));

I get this error:

Error 1 Member 'UnusedImageRemover.Form1.thread_search(string, System.Collections.Generic.List, System.Collections.Generic.List)' cannot be accessed with an instance reference; qualify it with a type name instead E:\Other\Projects\UnusedImageRemover\UnusedImageRemover\Form1.cs 149 46 UnusedImageRemover

Could you please tell me what I'm doing wrong?

Answer 1

You've got a static method, meaning it does not belong to an instance. this refers to the current instance, but since it's static, that doesn't make sense.

Just remove the this., and you should be good.

EDIT

Removing this. gets you a different exception. You are supposed to pass in a void delegate into the ThreadStart constructor, and you are invoking the method too early, and passing in the result (int[]). You can pass in a lambda instead, like:

static void Main(string[] args) {
    List<string> files = new List<string>(), images = new List<string>();
    string rootStr = "";

    var trd = new Thread(new ThreadStart(() => thread_search(rootStr, files, images)));
    trd.Start();
}

private static int[] thread_search(string root, List<string> files, List<string> images {
    return new[] { 1, 2, 3 };
}

Now the thread has a delegate to your search function, with a closure on the parameters - you'll want to read up on threads and closures if you're not familiar with them already.