SSIS For Loop Stopped working

I have a for loop container within my ssis package which contains a script and a sql task.

I have 3 variables.

source.string = this is folder location 
file.string = i have used wildcard = *.csv
exist.int = defaulted to 0

I have the innitexpression value set to @Exists=1 and the evalexpression value set to @Exists=1

in the script I have set it to look at source variable and if file.string variable exists then set exist variable to 1

problem is it just loops it should only loop if no file there. cant see how I've done this wrong it was working before I changed the variable to be a wildcard *.csv

I have tested it using another variable which contains a filename rather than a wildcard and it works correctly the issue is when looking for a wildcard for the filename followed by the extension. why is this? can I not pass through a wildcard variable?

my script task is

      public void Main()
        {
            // TODO: Add your code here
            string Filepath = Dts.Variables["User::Source"].Value.ToString() 
+ Dts.Variables["User::file"].Value.ToString();
            if (
                File.Exists(Filepath))
            {
                Dts.Variables["User::Exists"].Value = 1;
            }

            /// MessageBox.Show (Filepath);
            /// MessageBox.Show(Dts.Variables["Exists"].Value.ToString());
            Dts.TaskResult = (int)ScriptResults.Success;
        }

        #region ScriptResults declaration
        /// <summary>
        /// This enum provides a convenient shorthand within the scope of this class for setting the
        /// result of the script.
        /// 
        /// This code was generated automatically.
        /// </summary>
        enum ScriptResults
        {
            Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success,
            Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
        };
        #endregion

    }
}

Based on comments above i made 2 different solutions. The solution for you right now would be no. 2

This one can search for a specific file based on multiple files in your path. It need some tweaking but can be used if you wanna check if a specific file exists with wildcard

This one evaluates to true if any wildcard file is found.

C# Code 1

Using System.IO:

string Filepath = Dts.Variables["User::Source"].Value.ToString();
            string WildCard = Dts.Variables["User::file"].Value.ToString(); // In Text form @"*.txt";
            string fullpath = Filepath + WildCard;

            //With for loop
            string txtFile = null;
            // Gets all files with wildcard
            string[] allfiles = Directory.GetFiles(Filepath, WildCard);

            //Loop through all files and set the filename in txtFile. Do whatever you want here
            foreach(string fileName in allfiles)
            {
                //Check if a file contains something, it could be a prefixed name you only want
                if(fileName.Contains("txt"))
                {
                    txtFile = fileName;
                    if(File.Exists(txtFile))
                    {
                        Dts.Variables["User::Exists"].Value = 1;
                    }
                }
            }

C# Code 2

 Using System.IO;
 Using System.Linq;

 string Filepath = Dts.Variables["User::Source"].Value.ToString();
            string WildCard = Dts.Variables["User::file"].Value.ToString(); //In text form "*.txt";
            string fullpath = Filepath + WildCard;

            //With bool
            bool exists = Directory.EnumerateFiles(Filepath, WildCard).Any();

            if(exists == true)
            {
                Dts.Variables["User::Exists"].Value = 1;
            }


            MessageBox.Show (Filepath);
            MessageBox.Show(Dts.Variables["Exists"].Value.ToString());