[Solved] RadFilter - FieldEditors collection is empty

[Todd]

Server Error in '/' Application.

FieldEditors collection is empty.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: FieldEditors collection is empty.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[NullReferenceException: FieldEditors collection is empty.]
   Telerik.Web.UI.RadFilterDataFieldEditorCollection.System.Collections.Generic.IList<Telerik.Web.UI.RadFilterDataFieldEditor>.get_Item(Int32 index) +156
   Telerik.Web.UI.RadFilter.AddChildExpression(RadFilterGroupExpressionItem groupItem, Boolean isGroup) +118
   Telerik.Web.UI.RadFilterCommandEventArgs.ExecuteCommand(Object source) +173
   Telerik.Web.UI.RadFilter.OnBubbleEvent(Object source, EventArgs args) +185
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +70
   Telerik.Web.UI.RadFilterExpressionItem.OnBubbleEvent(Object source, EventArgs args) +131
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +70
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2981

I received the above error trying to dynamically create Rad Filters.  The error occurs on Postback when selecting to add a new filter expression.

I am using Telerik.Web.UI, Version=2013.1.403.35.

protected void Page_Load(object sender, EventArgs e)
{
    if (string.IsNullOrEmpty(this.FilterType))
        throw new NullReferenceException("FilterType must not be undefined.");

    var instance = Activator.CreateInstance("MyDLL, Version=1.0.0.0, Culture=neutral, PublicKeyToken=123456789", "MyDLL.Data.Biz.MetaData." + this.FilterType);

    PropertyInfo[] properties = instance.GetType().GetProperties(
        BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.Public);

    foreach (PropertyInfo p in properties)
    {

        RadFilterDataFieldEditor f = null;

        if (p.PropertyType == typeof(int))
        {
            f = new RadFilterNumericFieldEditor();
        }

        if (p.PropertyType == typeof(bool))
        {
            f = new RadFilterBooleanFieldEditor();
        }

        if (p.PropertyType == typeof(DateTime))
        {
            f = new RadFilterDateFieldEditor();
        }

        if (p.PropertyType == typeof(string))
        {
            f = new RadFilterTextFieldEditor();
        }


        if (f != null)
        {
            filter.FieldEditors.Add(f);
        }

        if (!Page.IsPostBack)
        {
            if (p.PropertyType == typeof(int))
            {
                f.DisplayName = p.Name.HumanizeString();
                f.DataType = typeof(int);
                f.FieldName = p.Name;
                f.ToolTip = p.Name;
            }

            if (p.PropertyType == typeof(bool))
            {
                f.DisplayName = p.Name.HumanizeString();
                f.DataType = typeof(bool);
                f.FieldName = p.Name;
                f.ToolTip = p.Name;
            }

            if (p.PropertyType == typeof(DateTime))
            {
                f.DisplayName = p.Name.HumanizeString();
                f.DataType = typeof(DateTime);
                f.FieldName = p.Name;
                f.ToolTip = p.Name;
            }

            if (p.PropertyType == typeof(string))
            {
                f.DisplayName = p.Name.HumanizeString();
                f.DataType = typeof(string);
                f.FieldName = p.Name;
                f.ToolTip = p.Name;
            }
        }
    }
}

Thanks for any insight.

[Antonio Stoilkov]

Hi Todd,

The exception could be thrown by incorrect field editors creation or if the FieldEditors collection is empty and does not have and field editors added to it. You could take a look at the help topic below which describes how to correctly add field editors dynamically in code behind. The idea is add the editors only in the initial page load. Additionally, could you confirm that you are adding at least one FieldEditor in the FieldEditors collection?

• http://www.telerik.com/help/aspnet-ajax/filter-adding-editors.html

Regards,
Antonio Stoilkov
Telerik