Filter.FireApplyCommand and grid created on Page_Init

[Dmitry]

Hello,
Below is how I initialize grid and filter

1. Page containing grid:

protected override void Page_Init(object sender, EventArgs e)
        {
            base.Page_Init(sender, e);
            Grid = new RadGrid(); // actually this is not RadGrid but descendant class I created
            Grid.Initialize(ZSheet, ForceLoad, DataSourceProvider, this); // create columns runtime
            ZSheetContainer.Controls.Add(Grid); 
            GridFilter.Initialize(ZSheet, Grid.ZTable.TableNameUser); 
            if (IsPostBack)
                GridFilter.ApplyFilter(); // create and apply filter expressions obtained from different source, see below
        }

2. Create filter expressions and editors:

public void ApplyFilter()
        {
            if (string.IsNullOrWhiteSpace(_hf.Value)) return;
            List<GridFilterItem> filterItems =
                new JavaScriptSerializer().Deserialize<List<GridFilterItem>>(_hf.Value);
            foreach (GridFilterItem item in filterItems)
            {
                ZSheetItem zitem = _table.Structure.FirstOrDefault(t => t.f_name == item.Condition.ColumnID);
                Type columnType = GetColumnType(zitem);
                Type filterExpressionType;
                Type[] types = new[] { columnType };
 
                switch (item.Condition.Operator)
                {
                    case GridKnownFunction.Contains:
                        filterExpressionType = typeof(RadFilterContainsFilterExpression);
                        break;
                    case GridKnownFunction.DoesNotContain:
                        filterExpressionType = typeof(RadFilterDoesNotContainFilterExpression);
                        break;
                    case GridKnownFunction.StartsWith:
                        filterExpressionType = typeof(RadFilterStartsWithFilterExpression);
                        break;
                    case GridKnownFunction.EndsWith:
                        filterExpressionType = typeof(RadFilterEndsWithFilterExpression);
                        break;
                    case GridKnownFunction.EqualTo:
                        filterExpressionType = typeof(RadFilterEqualToFilterExpression<>);
                        break;
                    case GridKnownFunction.NotEqualTo:
                        filterExpressionType = typeof(RadFilterNotEqualToFilterExpression<>);
                        break;
                    case GridKnownFunction.GreaterThan:
                        filterExpressionType = typeof(RadFilterGreaterThanFilterExpression<>);
                        break;
                    case GridKnownFunction.LessThan:
                        filterExpressionType = typeof(RadFilterLessThanFilterExpression<>);
                        break;
                    case GridKnownFunction.GreaterThanOrEqualTo:
                        filterExpressionType = typeof(RadFilterGreaterThanOrEqualToFilterExpression<>);
                        break;
                    case GridKnownFunction.LessThanOrEqualTo:
                        filterExpressionType = typeof(RadFilterLessThanOrEqualToFilterExpression<>);
                        break;
                    case GridKnownFunction.Between:
                        filterExpressionType = typeof(RadFilterBetweenFilterExpression<>);
                        types = new[] { columnType, columnType };
                        break;
                    case GridKnownFunction.NotBetween:
                        filterExpressionType = typeof(RadFilterNotBetweenFilterExpression<>);
                        types = new[] { columnType, columnType };
                        break;
                    case GridKnownFunction.IsEmpty:
                        filterExpressionType = typeof(RadFilterIsEmptyFilterExpression);
                        break;
                    case GridKnownFunction.NotIsEmpty:
                        filterExpressionType = typeof(RadFilterNotIsEmptyFilterExpression);
                        break;
                    case GridKnownFunction.IsNull:
                        filterExpressionType = typeof(RadFilterIsNullFilterExpression);
                        break;
                    case GridKnownFunction.NotIsNull:
                        filterExpressionType = typeof(RadFilterNotIsNullFilterExpression);
                        break;
                    default:
                        filterExpressionType = typeof(RadFilterEqualToFilterExpression<>);
                        break;
                }
 
                Type genericType = filterExpressionType.MakeGenericType(types);
                RadFilterExpression expression = (RadFilterExpression)Activator.CreateInstance(genericType, item.Condition.ColumnID);
                _filter.RootGroup.AddExpression(expression);
             }            
            _filter.FireApplyCommand();

}

 Now about the problem. When I call ApplyFilter from Page_Load() method, it raises a NullReferenceException in RadFilterDataEditor.CreateEditorFrom() method. When I call it from Page_Init() right after grid is initialized, filter won't apply. What am I doing wrong?
Thank you.

[Marin]

Hi Dmitry,

 When you construct a filter expression manually you should pass the field name and the value that you filter by. Also make sure that the FieldEditors collection of RadFilter is not empty at this time.
Here are a few help topics that can be useful in your scenario:
http://www.telerik.com/help/aspnet-ajax/filter-working-with-expressions.html
http://www.telerik.com/help/aspnet-ajax/filter-adding-editors.html

Regards,
Marin
the Telerik team

[Dmitry]

I have all required data - field name, function and compare value. Also I have all FieldEditors initialized and set up properly. I have read manuals from your website and set up everything just as said. Result - when I call it from Page_Load, I get a NullReferenceException, when I call it from Page_Init, I get neither exceptions nor filtering.

[Marin]

Hello Dmitry,

 Is the grid already databound at the time you try to apply the filter expressions? This is required because otherwise the filter query cannot be constructed properly. Depending on how you bind the grid it may not have requested the data yet on Page_Load.

Greetings,
Marin
the Telerik team

[Dmitry]

I bind datasource to grid in NeedDataSource handler so looks like it's not binded by the moment when filter is applied. I'll try this and report results.
But anyway, why I don't get NullReferenceException in Page_Init but have it raised in Page_Load?

[Marin]

Hi Dmitry,

 The NeedDataSouce normally fires during the PreRender event so in this case the grid will still not be bound on Page_Load. One option here might be to call the FireApplyCommand method later when the grid has bound to the data. The Page_Init event is too early in the life cycle and some of the controls may not have completely initialized yet so the code that throws an exception may not be even executed at this stage. 

Greetings,
Marin
the Telerik team

[Dmitry]

Hello,
I tried to apply filter from grid's DataBound handler but anyway I get the same error as in my first post

[Marin]

Hello Dmitry,

 Have you tried constructed and calling the filter expressions in the Page_PreRender event? Do you get the same exception there?

Greetings,
Marin
the Telerik team

[Dmitry]

Hello,
I had to suspend custom filtering development for few weeks but now we came to the point when we need it. So it's time to recall everything. Hopefully that was not me on Mars.
I tried to call FireApplyCommand from Page_PreRender handler and got the same result. Here is stack trace:

Telerik.Web.UI.RadFilterDataFieldEditor.CreateEditorFrom(RadFilterDataFieldEditor baseEditor) +17
   Telerik.Web.UI.RadFilterSingleExpressionItem.SetupFunctionInterface(Control container) +68
   Telerik.Web.UI.RadFilter.CreateFilterItems() +410
   Telerik.Web.UI.RadFilter.CreateControlHierarchy() +141
   System.Web.UI.Control.EnsureChildControls() +182
   Telerik.Web.UI.RadFilter.HandleApplyCommand() +38
   UpeWeb.ASPNET.UI.Controls.ZSheetGridFilter.ApplyFilter() in D:\Work\UpeWeb.ASPNET2\trunk\UpeWeb.ASPNET.UI\Controls\ZSheetGridFilter.cs:254
   UpeWeb.ASPNET.Views.ZSheetGridView.Page_PreRender(Object sender, EventArgs e) in D:\Work\UpeWeb.ASPNET2\trunk\UpeWeb.ASPNET\Views\ZSheetGridView.ascx.cs:67

Any comments/ideas about that? 
Thank you.

[Marin]

Hello,

 Before calling the FireApplyCommand method make sure that the _filter.FieldEditors collection is not empty. Also in this collection you should have a FieldEditor with FieldName equal to the one that you have specified in the filter expression: item.Condition.ColumnID. The stack trace indicates that there is no editor for such field.

Regards,
Marin
the Telerik team

[Rick]

Hi, I have a similar issue.
Actually I have duplicated the example almost exactly from the below URL
http://demos.telerik.com/aspnet-ajax/filter/examples/customeditors/defaultvb.aspx
and I get the below error in stack trace
[NullReferenceException: Object reference not set to an instance of an object.]
   System.Object.GetType() +0
   Telerik.Web.UI.RadFilterDataFieldEditor.CreateEditorFrom(RadFilterDataFieldEditor baseEditor) +17
   Telerik.Web.UI.RadFilterSingleExpressionItem.SetupFunctionInterface(Control container) +68
   Telerik.Web.UI.RadFilter.CreateFilterItems() +410
   Telerik.Web.UI.RadFilter.CreateControlHierarchy() +141
   System.Web.UI.Control.EnsureChildControls() +182
   System.Web.UI.Control.PreRenderRecursiveInternal() +60
   System.Web.UI.Control.PreRenderRecursiveInternal() +222
   System.Web.UI.Control.PreRenderRecursiveInternal() +222
   System.Web.UI.Control.PreRenderRecursiveInternal() +222
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4201

Additional information:  When I duplicate the above example in a web form without a master page then it works.  Unfortunately, my application is using a master page so it needs to work inside a master page.  I have pinpointed that I get the above error when I don't set the FilterContainerID.  If I set this parameter then I don't get the error but my custom field editors only show as simple text fields instead of dropdown or masked.  My ScriptManager is in the master page because it is needed for other pages.

Any ideas?

[Marin]

Hi,

 What kind of control are you trying to filter with RadFilter? In the demo there is an important part of code in the code behind file where we handle the ApplyExpressions event of RadFilter and construct the filter expressions of the grid, the custom editors are also created there in the PageLoad event. Do you have this code in your application as well? The demo should not depend on the presence of master page, maybe you have some other code that is executed there and causes problems.

Regards,
Marin
the Telerik team

[Rick]

Yes I have the Applyexpressions handler. As I said I have duplicated the example in a simple web form without master page which works perfect. Then I have exactly the same code in a web form with master page it doesn't work. In the example it is a radgrid, as I saidi have duplicated exactly the example. The filtered control is a radgrid in my code which is not working The only differences are the data source comes from SQL and the master page

[Marin]

Hi,

 You can find attached the duplicated example working with a master page.

I hope this helps.

Greetings,
Marin
the Telerik team

[Rick]

Thanks for the sample with master page.
Actually I ended up getting it to work on my own by copying the code which was working without masterpage over the same code that wasn't working with masterpage.  Then it worked.  I assume I must have had a small mistake somewhere but I couldn't say where.
Anyway thanks again.
Rick