c# open explorer and select file

// suppose that we have a test.txt at E:\
string filePath = @"E:\test.txt";
if (!File.Exists(filePath))
{
    return;
}

// combine the arguments together
// it doesn't matter if there is a space after ','
string argument = "/select, \"" + filePath +"\"";

System.Diagnostics.Process.Start("explorer.exe", argument);