Validate uploaded file extension

Question

Uploading files works fine but now I\'m trying to validate file extensions and looks like there\'s some interference between FileUpload1 and FileUpload2

Answer 1

bool CheckFileType(string fileName)
{
    string ext = Path.GetExtension(fileName);
    switch (ext.ToLower())
    {
        case ".gif":
            return true;
        case ".jpg":
            return true;
        case ".jpeg":
            return true;
        case ".png":
            return true;
        default:
            return false;
    }
}

if (CheckFileType(fuImage.FileName))
{
 //..........
}

or use RegularExpressionValidator: