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Try-catch FormatException

By : DonAjit
Date : September 29 2020, 04:00 AM
Any of those help Don't catch exceptions, but use int.TryParse(): nothing exceptionable in the user input (user can put any string and this is expected behivior).
code :
  if (int.TryParse(Console.ReadLine(), out int IloscPracownikow)) {
    // User input - Console.ReadLine() - is a valid integer (IloscPracownikow)
    object age = IloscPracownikow;
  else {
    // User input - Console.ReadLine() - is NOT a valid integer
    Console.WriteLine("Podaj liczbe, debilu");
 try {
   // Possible FormatException throw (if user input is not a valid integer)
   int IloscPracownikow = Int32.Parse(Console.ReadLine());

   // and this will never throw FormatException
   object age = IloscPracownikow;

   Console.WriteLine("Podaj rok zalozenia firmy.");

   // Possible FormatException throw
   int Rok = Int32.Parse(Console.ReadLine());

   listaFirm.Add(new Firma(NazwaFirmy, IloscPracownikow, Rok));
 catch (FormatException) {
   // either IloscPracownikow or Rok is invalid
   Console.WriteLine("Podaj liczbe, debilu");

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Catch Access DB Error (FormatException) And Return Custom Message?

By : user86748
Date : March 29 2020, 07:55 AM
Hope that helps Nevermind, I just went with this for now... It works, but if you guys can give me something better, please do.
code :
cmd.Parameters.Add("@MyData", OleDbType.Integer).Value = GetCellContents(worksheet2, "K8", "Int32")

 Private Function GetCellContents(ByVal worksheet As ExcelWorksheet, ByVal address As String, Optional ByVal type As String = Nothing) As Object
    If worksheet.Cells(address).Value Is Nothing Then
        Return DBNull.Value
        cellAddress = address
        Select Case type
            Case Is = "String"
                Return Convert.ToString(worksheet.Cells(address).Value)
            Case Is = "Int32"
                Return Convert.ToInt32(worksheet.Cells(address).Value)
            Case Is = "DateTime"
                Return Convert.ToDateTime(worksheet.Cells(address).Value)
            Case Else
                Return worksheet.Cells(address).Value
        End Select
    End If
End Function

Trying to catch a FormatException error fails. Only Exception can catch it?

By : erol özkan
Date : March 29 2020, 07:55 AM
Hope that helps BaseNumberConverter.ConvertFrom() internally calls a helper function to throw an exception:
code :
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
        catch (Exception e) {
            throw FromStringError(text, e);
    return base.ConvertFrom(context, culture, value);
internal virtual Exception FromStringError(string failedText, Exception innerException) {
        return new Exception(SR.GetString(SR.ConvertInvalidPrimitive, failedText, TargetType.Name), innerException);
catch (Exception ex) when (ex.InnerExcpetion is FormatException)
    // Catches nothing for some reason               
    MessageBox.Show("Caught FormatException\n\n" + ex.Message + "\n\n" + ex.InnerException);

catch (Exception ex)
    // This catches the error but InnerException says the error is of type FormatException.  
    // Yet FormatException doesn't catch it???
    MessageBox.Show("Caught Exception\n\n" + ex.Message + "\n\n" + ex.InnerException);

Why does a FormatException within `try` not get caught in `catch`?

By : shuanghu tao
Date : March 29 2020, 07:55 AM
I wish this helpful for you Try continuing debugging after the exception occurred. The message says that a first chance exception occured but you can continue the program. You should reach the breakpoint then. If there were no try.. catch block you would get an UNHANDLED exception.

Small coding project won't catch FormatException

By : Ryan Mason
Date : March 29 2020, 07:55 AM
may help you . So I recently started my first coding course for C#. I am currently trying to write a short program that prints out Yay! as many times as I indicate. Now to prevent any format exceptions, I've tried to add a try and catch to it. But, for some reason this isn't working and I can't seem to figure out why. The code is below: , It's
code :
 var number = int.Parse (entry);
  Console.Write("Enter the number of times to print \"Yay!\": ");
  string entry = Console.ReadLine();
  bool print = true; 

  try {      
    // int.Parse is within the try {} scope now
    var number = int.Parse (entry);

    while(print) {
  catch(FormatException) {
    Console.WriteLine("You must enter a whole number.");
  Console.Write("Enter the number of times to print \"Yay!\": ");

  int number;

  if (!int.TryParse(Console.ReadLine(), out number)) {
    Console.WriteLine("You must enter a whole number.");


  bool print = true;

  // There's no need in try {} catch {} now
  while(print) {

try-catch-finally formatexception

By : Luke Webber
Date : March 29 2020, 07:55 AM
wish help you to fix your issue Instead of using an exception to do this, it'd be better to use DateTime.TryParse. This will return a simple true or false if it can be converted into a date.
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