How to insert new row in GridView?

Its been a while since I did some custom work on controls like GridView, DataGrid etc. Last week I was working on a prototype of some application that required me to add some records into the database. So I decided to give GridView control in ASP.Net a try. I needed a very simple UI so I decided to use as much built in functionality of this control. Since I needed to add a new record, so I needed a way to be able to add a new row into GridView. So I looked at the CommandField column. One of the properties it has is ShowInsertButton . So I added this property and set it to true. So now my mark up on ASP.Net on the page looked as shown below.

<Columns>
 <asp:CommandField ShowEditButton="True" 
    ShowDeleteButton="true" 
    ShowInsertButton="true"></asp:CommandField>
 .... othe bound columns.
</Columns>

I ran the application and my grid shows up and has all three data manipulation links visible. So I clicked on New link button. Well, I did not see an empty row appear where I was going to add new data for new row in database. I checked, everything looked in order. I have event handler correctly mapped and code looked fine. After trying few things around, I searched on internet. I could not find any useful information on why my event is not firing or why new row is not getting added. All the posts and articles that I ran into talked about adding a new button in the grid to accomplish taks of added new records. Well that sounded a little odd that why would I need to add my own button when there is already a command link buttoon available. Thats when I decided to read the documentation on this property ShowInsertButton. Here is something in documentation that stood out.

This property applies only to data-bound controls that support insert operations, such as the DetailsView control.

When you look at various events in GridView control, you will not find any related to Insert. Now that explained why I am not getting new row added to my grid.

Adding new row to GridView

So here is quick solution that I came up with for my prototype. When you click on New link button in GridView, it does fire RowCommand event. Here you can check for CommandName value of New. In this event handler, I added a new empty record into the data source to which my GridView was bound, set the EditIndex of the grid to first record and bind the grid again. Now I have an empty row in Edit mode open for me to add some data.

if (e.CommandName == "New")
{
 ViewState["_inserting_"] = 1;
 var glossaryTerm = new Services.GlossaryTerm();
 _terms.Insert(0, glossaryTerm);
 GlossaryGrid.EditIndex = 0;
 BindGrid();
}

You can see that I added a flag in ViewState that grid is in Insert mode. The reason for this is that since GridView does not support Insert directly, when you will click on Update link button, you are going to get RowUpdated event handed to you. So you will need some way of knowing that this record is actually to be added and not edit some existing one. The way I did is not one of the best and elegant way. But you get the idea. One nice of doing is to have an hidden field where some unique ID of each record is stored. And you can keep this field hidden. Since I did not have any unique ID in my data source, I had to do it differently. But most grids are bound to some data source with some unique ID. So when you add a new empty record for adding, you can set its Unique ID value to some token valur like -1. When you handle RowUpdated event, then you can look for this unique ID value and perform the database accordingly.

This trick should allow you to use built in command buttons to add new row in GridView.