Sorting and filtering on a Custom DataSource

If you want to add a SPGridView to an Application Page in SharePoint and link it to a DataSource, you will have to write some extra code for sorting and filtering. I found quite some examples on different blogs, but still had to find out things on my own. Especially because I couldn’t find any code example that used a DataView as return type. So I’m not going to describe in detail the complete process, but only the steps related to a DataView return type.

In your Application Page you will have to add a reference to your assembly containing the DataSource. Next you add a tag for the DataSource, give it an ID and reference this ID in the SPGridView DataSourceID attribute. If you want sorting and filtering, like I do in this example, you set AllowSorting and AllowFiltering to true. For the filtering you have to define the FilterDataFields, FilteredDataSourcePropertyName and the FilteredDataSourcePropertyFormat. Suppose I only display four fields (Name, Type, Status and Description) of our DataSource and I only want to filter on Type and Status.

 

Adding pagers to a grid inside a WebPart

When you want to add a pager to a grid inside a WebPart to implement paging, you will notice that some event handlers can be left blank. Suppose you create a new SPGridView in the CreateChildControls, set paging to true and PageSize to something less than the amount of records you are going to add and you add that grid to the WebPart controls. Next you add a toolbar to the WebPart controls and create a new SPGridViewPager. Assign the Id of the grid to the GridViewId of the pager, add some handlers for the ClickNext and ClickPrevious event and add the control to the ToolBar controls. You can just implement the Click functions and leave them empty. In the OnPreRender you add the datasource to the grid and bind the grid. Easy to implement, nothing to worry about.

Code example:
Protected Overrides Sub CreateChildControls()
  grid = New SPGridView()
  grid.ID = Me.ID + “Grid”
  grid.AllowPaging = true
  grid.PageSize = 10

  pager = New SPGridViewPager()
  pager.ID = Me.ID + “Pager”
  pager.GridViewId = grid.ID
  AddHandler pager.ClickNext, AddressOf pager_ClickNext
  AddHandler pager.ClickPrevious, AddressOf pager_ClickPrevious

  gridToolBar = Page.LoadControl(“~/_controltemplates/ToolBar.ascx”)
  gridToolBar.RightButtons.Controls.Add(pager)

  Me.Controls.Add(grid)
  Me.Controls.Add(gridToolBar)
End Sub

Protected Overrides Sub OnPreRender(ByVal e as EventArgs)
  MyBase.OnPreRender(e)

  ‘No further details about the method below.
  ’It adds a datasource to the grid with more
  ’than 10 records.
  grid_AddDataSource()

  grid.DataBind()
End Sub

Private Sub pager_ClickNext(ByVal sender As Object, ByVal e As EventArgs)
  ‘Intentionally left blank, grid is binded in OnPreRender
End Sub
Private Sub pager_ClickPrevious(ByVal sender As Object, ByVal e As EventArgs)
  ‘Intentionally left blank, grid is binded in OnPreRender
End Sub

You will see that first the CreateChildControls is called, next a click handler and as last the OnPreRender. During the click handler, the current pageindex is updated automatically.