how to check if something is only numbers in delphi

To check if a string contains only numbers in Delphi, you can use the StrToIntDef function and check if it raises an exception. Here's an example:

function IsNumeric(const Str: string): Boolean;
  Value: Integer;
    Value := StrToIntDef(Str, 0);
    Result := True;
    Result := False;

In the example above, the IsNumeric function takes a string Str as input and tries to convert it to an integer using StrToIntDef. If the conversion is successful, it means the string contains only numbers, and the function returns True. Otherwise, if an exception is raised, it means the string contains non-numeric characters, and the function returns False.

You can use this function to check if a string contains only numbers in Delphi. For example:

if IsNumeric('12345') then
  ShowMessage('The string contains only numbers')
  ShowMessage('The string contains non-numeric characters');

This will display a message box indicating whether the string contains only numbers or not.

Please note that the IsNumeric function only checks if the string contains integer numbers. If you need to check for floating-point numbers or other numeric formats, you may need to modify the function accordingly.

I hope this helps! Let me know if you have any further questions.