Custom Validation in LightSwitch 2012

This article shows how custom validation works in LightSwitch using Visual Studio 2012.

The following procedure describes how to create a sample showing how to write custom validations for the specified fields in the table.

Step 1

Open the Solution Explorer.

sol ex.jpg

Step 2

In the Solution Explorer, right-click on the "Data Source" and choose "Add Table".

Add table.jpg

Step 3

The table appears.


Step 4

Now we will start the validation process on various fields in a table. Select a field from the table as in the following.


Now go to the property window, there is a validation field from where you can apply the validations. You can do the same for the college field.

prop name.jpg

Step 5

This time we will select the Intime field and go to the property window, under the validation tab there is a minimum and maximum value field.

intime field.jpg

Property Window


There is a custom validation link by which you can write your own code for validation.

custom validation.jpg

Step 6

Click on the custom validation link for the InTime field and apply your own logic.

partial void InTime_Validate(EntityValidationResultsBuilder results)
"InTime is always smaller than OutTime");

Step 7

Similarily you can do it for the OutTime field by first going to the property window, fill in the minimum and maximum values then click on the custom validation link for the OutTime field.


We will provide the following code:

partial void OutTime_Validate(EntityValidationResultsBuilder results)
"OutTime is always greater than InTime");

Step 8

Once again go to the Solution Explorer and right-click on the screen and choose "Add Screen".

add src.jpg

Step 9

The Add New Screen dialog box appears. Select the "Editable Grid Screen" from the Screen Template and under the screen data choose "Student" and click "OK".


Step 10

The Screen Designer appears.

src desi.jpg

Step 11

Press F5 to run the application.

mt output.jpg

Now we wil add some records and we will see that the information is automatically provided to the "InTime" and "OutTime" fields.

by default.jpg

Insert some records inro the fields and we will see the validation occur.

validation in output.jpg

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