What property values does GridView retain across data binding operations ( besides SelectedIndex )?

Question

1) Suppose GridView1 is bound to ObjectDataSource and that GridView1.SelectedIndex is set to value 7. If we then rebind GridView1 by calling GridView1.DataBind(), GridView.SelectedIndex will still retain its initial value ( 7 ).

Are there any other properties which GridView remembers across rebinding operations?

2) Suppose GridView1 is bound to ObjectDataSource control. When GridView1’s row gets deleted, we can call GridView1.DataBind() inside GridView1.RowDeleted event handler to retrieve values from data source. If we don’t call Gridview1.DataBind inside that event handler, then DataBind() will automatically be called by Asp.Net and the result will be the same.

So are there any reasons why we should manually call GridView.DataBind( inside RowDeleted event handler ) instead of letting Asp.Net call it automatically?

Answer 1

Your answer lies in Page.DataBind and Control.DataBind methods. The main difference is that all data sources are bound to their server controls after the Page.DataBind method is called. No data is rendered to the control until you explicitly call either the DataBind method of the Web server control or until you invoke the page-level Page.DataBind method. Typically, Page.DataBind (or DataBind) is called from the Page_Load event. Source

Particular answer for 1) is there's no such property for GridView,but you can make your own one and add last changed control.(Ideal)

For 2)Your action here coming from a postback,because the default bound source is changed after all you deleted a row inside it,since default source cannot be bound again,you need to call DataBind manually.

Answer 2

I'm going to mention a bit about Hierarchical Data Binding for starters.
In order to bind a datasource to a server-side control (GridView,DetailsView,.. etc) , that control must support a property known as DataSource and a method known as DataBind() , and the datasource that control is bound implement IEnumerable interface.

There is an exception for DataSet and DataTable which can be both bound directly , which results in binding to the default DataView of default table.

To bind a data to a control , you assign the data source to the DataSource property of the control and call its DataBind() method.Source

Since in your case ,databinding situation is different as you mentioned earlier that you bind GridView with ObjectDataSource which executes a query in page load and in every SELECT,INSERT,UPDATE,DELETE operations,datasource is bound automatically (which means DataBind is also called automatically).

There is another case which you are looking for an answer in the first place is that if datasource is queried and bound in page events (i.e. you query something and get a result with DataTable and bind it into GridView --> this source is not in the page not a objectdatasource or something else stands on page as static source).Since this query is coming from an event,when you enable pageIndex you must query it again that leads to you must also bind it with DataBind.

DataTable sourceTable = GetDataFromServer();
gridView.DataSource = sourceTable;
gridView.DataBind();

I hope that you can understand this time.