C# Checking a File exists in Folder

How to get all files from a folder and compare a whether that file exists in that folder or not. Here is a sample code where you can loop through the code and check the file.

I have declared a variable to check there it exists or not.

private bool isFileExists = false;

Now I have this code to check whether file exists and based on it I’ll redirect in to that page.

string searchfolder = Server.MapPath("~") + "\\TestFolder";
DirectoryInfo Dir = new DirectoryInfo(searchfolder);
FileInfo[] FileList = Dir.GetFiles("*.aspx", SearchOption.AllDirectories);
foreach (FileInfo FI in FileList)
{
    if (FI.Name == redirectPage)
    {                            
        isFileExists = true;
        break;
    }                       
}
if (isFileExists == true)
{
    Response.Redirect("~/redirectPage");
}
else
{
    Response.Redirect("~/OtherRedirect.aspx");
}

Here I have search pattern as *.aspx as I need to check these files. This can be based on the files you want to check