As we learned from the previous tutorials about the ASP.Net Gridview control containing checkbox controls to generate the output like a checkbox list. There we developed the functionality to check/uncheck the checkbox controls and maintained their state while performing paging action on the records displayed in the gridview control. In this tutorial we learn the VB.net code along with JavaScript snippet to validate the checkbox controls so that the user could not select the checkbox items more than the specified limit.

Please refer the previous tutorial about maintaining the checkbox state while GridView paging using vb.net -2 to understand the functionality of re-populating the checkbox controls placed inside the GridView control. In the previous article we used a VB.Net selectedCheckboxes function having the functionality to store the state of checkbox controls while GridView paging. Here we will learn how to populate the checkbox controls from the values saved in the HiddenField i.e. hiddenCatIDs.

In the first part of this tutorial for Maintaining the checkbox state while GridView paging using VB.Net - 1 we discussed about the HTML code layout for GridView control TemplateField column, checkbox server control and DataKeyNames property to store the unique key value for each row of the ASP.Net GridView control. Now, next you need the mechanism to maintain the checkbox state while GridView paging. You can maintain the checkbox state using two methods:

In ASP.Net, GridView paging does not provide any functionality to maintain the checkbox state whether it was in checked or unchecked state before executing the paging event. Yes it's easy to get and set the checkbox states inside the ASP.Net GridView control based on the values retrieved from the database. This process is easy only if you have set the AllowPaging property of GridView control to "false" which means when you are not using the paging feature of GridView.

Select all ASP.Net GridView Checkbox controls with single click functionality can also be accomplished by using Javascript client side scripting. In the previous tutorial about GridView Checkbox select all using VB.Net we learned the server side coding to select all the checkboxes in a single click. Here we will discuss the use of Javascript client end script code to select all the checkboxes placed inside the GridView column.

In this tutorial we will discuss the VB.Net server end code to select all checkboxes placed inside the GridView control. First of all you need to setup the GridView layout with checkbox controls placed inside its ItemTemplate column.

The value of Checkbox control placed inside the ASP.Net GridView control can be accessed using the same method that we discussed in the previous tutorial of GridView FindControl Checkbox using VB.Net. The FindControl function returns the server control object as a naming container of server control. This same FindControl function can be used to access the server controls and their values placed inside the ASP.Net GridView Columns.

The FindControl function with ASP.Net GridView control can be used to access the Checkbox control placed inside the ItemTemplate of TemplateField Column. FindControl function returns the naming container of the server control (e.g. checkbox in this tutorial) who's ID is passed to the function. The VB.Net FindControl function searches the server control within the row items and column of the GridView control.

After designing the HTML layout of GridView control by placing checkbox control in the ItemTemplate next step is to bind the data with GridView control. In this tutorial for ASP.Net GridView checkbox control we have used VB.Net code to connect and bind the data with GridView control using categories table of SQL Northwind database.

In the previous tutorial we learnt how to edit and update the SelectedValue of DropDownList placed inside the GridView control separately for each row using RowUpdating event. Here we will learn the VB.Net code to update all the DropDownList selected values placed inside the GridView Control into the SQL database table i.e. tbl_orders all at once with a single click on a link button control.