Validating text box in vb
Why not just use a Required Field Validator and make sure it is correct? Page Protected Sub Button1_Click(By Val sender As Object, By Val e As System. For instance if you wanted the user to enter a user name, but the field did not require validation, the user could submit a blank entry or one with invalid characters that you would not want.
Here you can see some useful techniques that accept only numbers in the textbox.
The default value for this property is True, so you don't have to modify it for the other controls.
Run the sample program on the companion CD, type something in the required Text Box, and then move to the second field.
In the toolbox panel, drag three Text Box items inside the div tags followed by two break lines. In the toolbox panel, drag a Button item below the last set of break tags. In the toolbox, look in the validation section and drag a Required Field Validator after each text box. Click on Required Field Validator1 and in the properties window look for ‘Control To Validate’. Repeat for Required Field Validator2 (enter Text Box2) and Required Field Validator3 (enter Text Box3). For all Required Fieldvalidators, change the Error Message to ‘*‘ (an asterisk) and change the Fore Color to Red. In the toolbox panel, drag a Label item after the closing button tag and delete it’s text. Basically we are just adding the text value from each text box to the label.
Double click on Button to bring up the Button1_Click event handler.