Forcing Alpha Character Entry

OBJECT Form 50900 ValidateLetters
{
  OBJECT-PROPERTIES
  {
    Date=07/14/09;
    Time=[ 1:53:03 PM];
    Modified=Yes;
    Version List=;
  }
  PROPERTIES
  {
    Width=8000;
    Height=8000;
  }
  CONTROLS
  {
    { 1000000000;TextBox;4510 ;550  ;1700 ;440  ;SourceExpr=TestInput;
                                                 OnValidate=BEGIN
                                                              Valid := LetterValidate(TestInput);
                                                            END;
                                                             }
    { 1000000001;Label  ;1100 ;550  ;3300 ;440  ;ParentControl=1000000000 }
    { 1000000002;TextBox;4510 ;1210 ;1700 ;440  ;SourceExpr=ResultASCII }
    { 1000000003;Label  ;1100 ;1210 ;3300 ;440  ;ParentControl=1000000002 }
    { 1000000006;CheckBox;4510;2090 ;440  ;440  ;ShowCaption=No;
                                                 SourceExpr=Valid }
    { 1000000007;Label  ;1100 ;2090 ;3300 ;440  ;ParentControl=1000000006 }
  }
  CODE
  {
    VAR
      TestInput@1000000000 : Text[30];
      myChar@1000000001 : Char;
      ResultASCII@1000000002 : Integer;
      Valid@1000000003 : Boolean;

    PROCEDURE LetterValidate@1000000000(Text@1000000000 : Text[100]) : Boolean;
    VAR
      i@1000000001 : Integer;
    BEGIN
      FOR i := 1 TO STRLEN(Text) DO BEGIN
        myChar := Text[i];
        ResultASCII := myChar;

        IF NOT (myChar IN [65..99,97..122]) THEN
          EXIT(FALSE);
      END;
      EXIT(TRUE);
    END;

    BEGIN
    END.
  }
}

If you want users to only enter uppercase letters in this field, enter AZ. This ensures that only uppercase characters in the range of A-Z are accepted. If you want both uppercase and lowercase characters, leave this value blank.

You can specify multiple ranges of characters by entering the parameters in pairs. For example, a value of admpzz indicates that only the following characters are accepted: a, b, c, d, m, n, o, p, and z. If you only want to allow a single character, then enter that character twice to specify a starting and ending range.

For text boxes, you can use this property to further limit the characters allowed, based on the field's setting.

The setting for the text box and the field is checked during validation.

If you want users to only enter uppercase letters in this field, enter AZ