Determine if a file is valid based on a default list

public static bool GetValidFile(FileUpload fu)
{
bool result = false;
try
{
List fileType = new List();
fileType.Add("DOC");
fileType.Add("TXT");
fileType.Add("XLS");
fileType.Add("PPT");
fileType.Add("PDF");
fileType.Add("DOCX");
fileType.Add("WMV");
fileType.Add("XLSX");
fileType.Add("PPTX");
fileType.Add("WMA");
fileType.Add("MP4");
fileType.Add("3GP");
fileType.Add("M4A");
fileType.Add("MP4V");
fileType.Add("M4P");
fileType.Add("M4B");
fileType.Add("3GPP");
fileType.Add("3GP2");
fileType.Add("MOV");
fileType.Add("RTF");
fileType.Add("CSV");
fileType.Add("RTF");
if (fu.HasFile)
{
string fileExt;
fileExt = fu.FileName.Substring(fu.FileName.LastIndexOf('.') + 1).ToUpper();
if (fileType.Contains(fileExt))
{
result = true;
}
else
{
result = false;
}
}
}
catch (Exception ex)
{
result = false;
}
return result;
}

To use the above, do this:

if (Utility.GetValidFile(fuAttach) == false)
{
string fileerrormessage = "Invalid file type was selected for attachment, please upload a valid file type.";
fileerrormessage += "
Allowed file types are: .DOC, .TXT, .XLS, .PPT, .PDF, .DOCX, .WMV, .XLSX, .PPTX,
.WMA, .MP4, .3GP, .M4A, .MP4V, .M4P, .M4B, .3GPP, .3GP2, .MOV, .RTF, .CSV.";
lblError.Text = fileerrormessage;
lblErrorTop.Text = fileerrormessage;
return;
}

int fileSize = fuAttach.PostedFile.ContentLength;
if (fileSize > (maxFileSize * 1024))
{
lblError.Text = "File size is too large. Maximum file size permitted is " + maxFileSize + "KB";
lblErrorTop.Text = "File size is too large. Maximum file size permitted is " + maxFileSize + "KB";
return;
}