How to Compare Listbox item(s) with Array Items

Question

I have one check box which contains some exe/application names. When i am going to select any one of them then it should start. Now application is starting but if i have selected exe/application name from check box which does not exists in path(which i have written below), i.e. how to put validation on that. My code is:

if (chkListBox.CheckedItems.Count > 0)
{
    for (int i = 0; i < chkListBox.CheckedItems.Count; i++)
    {
        string path = @"D:\Development\Latest\ConsoleApplication1\ConsoleApplication1\bin\Debug";
        string files = Directory.GetDirectoryRoot(path);
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = Path.Combine(path, chkListBox.Items[i].ToString() + ".exe")
            }
        };

        process.StartInfo.UseShellExecute = false;// Beacuse I  am using Process class
        process.StartInfo.CreateNoWindow = true;
        process.Start();
    }
}
else
{
    MessageBox.Show("Item Not  selected");
}

Answer 1

string path = @"D:\Development\Latest\ConsoleApplication1\ConsoleApplication1\bin\Debug";
string files = Directory.GetDirectoryRoot(path);

var exeNotFoundList = new List<string>();

for (int i = 0; i < chkListBox.CheckedItems.Count; i++)
{
    var exeFilePathWithName = Path.Combine(path, chkListBox.Items[i].ToString() + ".exe");
    if(!File.Exists(exeFilePathWithName))
    {
         exeNotFoundList.Add(exeFilePathWithName);
         continue;
    }
    var process = new Process
        {
            StartInfo = new ProcessStartInfo
               {
                  FileName = exeFilePathWithName
                }
         };

   process.StartInfo.UseShellExecute = false;// Beacuse I  am using Process class
   process.StartInfo.CreateNoWindow = true;
   process.Start();

}

if(exeNotFoundList.Count > 0)
{
    var errorMessage = String.Join(String.Empty, exeNotFoundList.ToArray());
    MessageBox.Show(errorMessage);
}