Passing string to int to substring

I currently get the users number like this:

        if (checkBox1.Che开发者_如何转开发cked)
        {
            rchars = numericUpDown1.Value.ToString();
        }
        else
        {
            rchars = "3";
        }

string rchars; is a global variable.

So, I'm trying to remove the rchars from file names. For example the first three characters from the file name:

            int num = Int32.Parse(rchars);
            foreach (FileInfo name in fpaths.GetFiles("*.mp3")
            {
                string snub = name.Name.Substring(num);
                MessageBox.Show(snub);
                System.IO.File.Move(blah + name.Name, newblah + snub);
            }

My question is how can I get "num" to work in a substring? Since I can't get it to be a value. Since I want to pass it from the numericUpDown. Add make "num" a value so I can remove the value from the file names.

Thanks.

Value property of NumericUpDown is Decimal - that is perhaps why you are having issues. In your if block, I would consider casting the Value Property of NumericUpDown object into an integer in the true part and use integer value 3 in its else part. There after, I would avoid parsing again and give it to Substring as is.

You say you want to remove all occurrences of rchars from name, so why are you using Substring? If you want to remove the string rchars from name then just keep it as a string and use String.Replace:

string snub = name.Name.Replace( rchars, String.Empty );

Also, the Value property of a NumericUpDown is a decimal, not an int.

are you looking to replace the value "3" within the name of a file with something else/remove it? Like this:

original file:

string fiename = "myfile3.mp3";

remove/replace selected number (in this case 3):

string num = "3";
filename.replace(num, "");

should end up with a filename "myfile.mp3"