在gridview中删除列并对其重新排序，并在回发中持久化

Question

I have a page on which GridView is used to show records. Now I allowed the user to customize the GridView view by changing order of columns or adding removing columns from predefined list of columns. OnPagePrerender event I am removing all the cells from GridView and adding cells with the order selected by user. Its working fine but when a PostBack is occurred then it throws an exception ie

Failed to load ViewState. etc.

Because now the cells are not the same as they were saved in ViewState .

What I want is to persist these changes that I have made to GridView on PostBack ?

Answer 1

You have to save the GridView (or your data recordset) in the VIEWSTATE and reload the Gridview only from the VIEWSTATE.

So in other words, only query the database when the data has to change, but you have to structure the recordset in a way that the gridview can display it, the way the data has loaded , ie dynamic SQL, with your order of columns as needed.

Then save the recordset into a viewstate variable, and refer to it in your gridview when a postback is made.

I did something similar with rows, not columns, and yeah you can't rely on the default datasource or datasourceID anymore when the gridview control is being manipulated at that deep level.

Answer 2

For this you have to create a new order of you Gridview columns.

First make copy of your columns. Second reorder your columns.

var columns = GridView1.Columns.CloneFields(); // makes a copy of gridview columns
GridView1.Columns.Clear(); // remove all the columns

// now make any order for your gridview columns
GridView1.Columns.Add(columns[3]); // e.g. now your column 4 is placed at first position
GridView1.Columns.Add(columns[0]); // here column 1 is placed at second position