Validate a control in a simple way

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- How to validate a control in a simple way?

 

The following steps have to be performed to create a validation setup for a control:

 

1.Place an error provider component on a form, e.g TLMDHintErrorProvder (TLMDHintErrorProvder1), set up its properties as desired;
2.Place a validator component on a form, e.g. TLMDRegExpValidator (LMDRegExpValidator1);
3.Set up the properties of the validator component, e.g. set RegExp property of LMDRegExpValidator1 to '^[\d]+$' to allow values which represent non-negative integer numbers and ErrorMessage to 'The field %F should contain a non-negative integer number!' (where %F is a placeholder for the field name);
4.Set ErrorProvider property of LMDRegExpValidator1 to TLMDHintErrorProvder1;
5.Place a validated input control on a form, e.g. TLMDEdit (LMDEdit1);
6.Set Validator property of LMDEdit1 to LMDRegExpValidator1, ErrorMsgString property to 'Edit1'.

 

Now if the text in LMDEdit1 doesn't represent a non-negative integer number, a hint message will appear: 'The field Edit1 should contain a non-negative integer number!', if it does, the hint message will disappear.