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Sorting problem with Inheritance

9 Answers 133 Views

Grid

This is a migrated thread and some comments may be shown as answers.

Rafael asked on 24 Apr 2009, 01:28 PM

Hi developers,

I'm using a List of objects to fill my Grid. The objects type is a class that inherits from another class. My grid shows the fields correctly, but if I try sort, I get some strange errors. When I try to sort by a field from the base class, I get an error (Cannot find the column '...'). If I try sort by a field from the child class (used as DataSource), the Grid is sorted correctly.

My Telerik version is Q3 2008.

Following, I try to exemplify the situation.

My classes:

    
            public class ClassA  
        
            {  
        
               public string ID { get; set; }  
        
               public string Name { get; set; }  
        
            }  
        
            public class ClassB : ClassA  
        
            {  
        
               public string ZipCode { get; set; }  
        
            }

My Page:

    
            radGrid_NeedDataSource(object source, GridNeedDataSourceEventArgs e)  
        
            {  
        
                List<ClassB> list = getData();  
        
                radGrid.DataSource = list;  
        
            }

If I try to sort by ZipCode, the Grid is sorted.
If I try to sort by Name or ID, I get the error "Cannot find column".

9 Answers, 1 is accepted

answered on 24 Apr 2009, 02:23 PM

Hi Rafael,

I tried the scenario and its working fine in my end. Here's the code which I tried.

Class definitions:

    
            public class ClassB:ClassA 
        
            { 
        
                public ClassB() 
        
                { 
        
                    // TODO: Add constructor logic here 
        
                } 
        
                private string zipCode; 
        
                public string ZipCode 
        
                { 
        
                    get 
        
                    { 
        
                        return zipCode; 
        
                    } 
        
                    set 
        
                    { 
        
                        zipCode = value; 
        
                    } 
        
                } 
        
            } 
        
            public class ClassA 
        
            { 
        
                public ClassA() 
        
                { 
        
                    // TODO: Add constructor logic here 
        
                } 
        
                private string id; 
        
                private string name; 
        
                public string ID { get 
        
                { 
        
                    return id; 
        
                } 
        
                set 
        
                { 
        
                    id = value; 
        
                }         
        
                    } 
        
                public string Name { 
        
                    get 
        
                    { 
        
                        return name; 
        
                    } 
        
                    set 
        
                    { 
        
                        name = value; 
        
                    } 
        
                } 
        
            }

CS:

    
            private void Bind() 
        
                { 
        
                    ClassB b = new ClassB(); 
        
                    b.ID = "1"; 
        
                    b.Name = "one"; 
        
                    b.ZipCode = "onezip"; 
        
                    IList<ClassB> list = new List<ClassB>(); 
        
                    list.Add(b); 
        
                    ClassB b1 = new ClassB(); 
        
                    b1.ID = "2"; 
        
                    b1.Name = "two"; 
        
                    b1.ZipCode = "twozip"; 
        
                    list.Add(b1); 
        
                    RadGrid1.DataSource = list; 
        
                    //RadGrid1.DataBind(); 
        
                }

Thanks,
Shinu.

answered on 24 Apr 2009, 11:01 PM

How about an interface that implements another interface? It appears properties with value types do not work (sorting fails), but object properties work?

See this example (customized a Telerik forum example). I have two interfaces where IInterface2 : IInterface1. The sorting in the grid fails for ID (defined in Interface1) but works for Child.Name (defined in Interface 1 as well).

    
            using System.Collections.Generic; 
        
            using Telerik.Web.UI; 
        
            public partial class _Default : System.Web.UI.Page  
        
            {     
        
                protected void GridSource(object sender, GridNeedDataSourceEventArgs e) 
        
                { 
        
                    List<IInterface2> data = new List<IInterface2>(); 
        
                    for (int i = 0; i < 5; i++) 
        
                    { 
        
                        MyObject item = new MyObject { ID = i, Text = "Text " + i, Child = new NestedObject { Name ="Name " + i} }; 
        
                        data.Add(item); 
        
                    } 
        
                    RadGrid1.DataSource = data; 
        
                } 
        
            } 
        
            public interface IInterface1 
        
            { 
        
                int ID { get; set; } 
        
                NestedObject Child { get; set; } 
        
            } 
        
            public interface IInterface2 : IInterface1 
        
            { 
        
                string Text { get; set; } 
        
            } 
        
            public class MyObject : IInterface2 
        
            { 
        
                public int ID { get; set; } 
        
                public string Text { get; set; } 
        
                public NestedObject Child { get; set; } 
        
                public MyObject()  
        
                {  
        
                    // TODO: Add constructor logic here  
        
                } 
        
            } 
        
            public class SuperClass 
        
            { 
        
                public int SuperID { get; set; } 
        
                 public SuperClass()  
        
                {  
        
                    // TODO: Add constructor logic here  
        
                } 
        
            } 
        
            public class NestedObject 
        
            { 
        
                public string Name { get; set; } 
        
            }

    
            <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 
        
            <%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %> 
        
            <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
        
            <html xmlns="http://www.w3.org/1999/xhtml"> 
        
            <head runat="server"> 
        
                <title></title> 
        
            </head> 
        
            <body> 
        
                <form id="form1" runat="server"> 
        
                <asp:ScriptManager runat="server" ID="SMNGR"> 
        
                </asp:ScriptManager> 
        
                <div> 
        
                    Bound on NeedDataSource 
        
                    <br /> 
        
                    <br /> 
        
                    <telerik:RadGrid runat="server" ID="RadGrid1" AutoGenerateColumns="false" AllowSorting="true" 
        
                        OnNeedDataSource="GridSource"> 
        
                        <MasterTableView> 
        
                            <Columns> 
        
                                <telerik:GridBoundColumn DataField="ID" HeaderText="ID"> 
        
                                </telerik:GridBoundColumn> 
        
                                <telerik:GridBoundColumn DataField="Text" HeaderText="Text"> 
        
                                </telerik:GridBoundColumn> 
        
                                <telerik:GridTemplateColumn HeaderText="Name" SortExpression="Child.Name"> 
        
                                    <ItemTemplate> 
        
                                        <%#Eval("Child.Name") %> 
        
                                    </ItemTemplate> 
        
                                </telerik:GridTemplateColumn> 
        
                            </Columns> 
        
                        </MasterTableView> 
        
                    </telerik:RadGrid> 
        
                </div> 
        
                </form> 
        
            </body> 
        
            </html>

answered on 23 Sep 2009, 04:08 PM

Hello,

The general case is as follows: If you have a collection of base class objects, RadGrid works only with base class properties. The same goes for a collection of derived class objects, i.e. both base class and derived class properties should be visible to RadGrid. The GridTableView class now provides a property named RetrieveDataTypeFromFirstItem that causes RadGrid to use the first item type as a template for the properties of all the remaining items in the collection.

Darren, you seem to define a collection of base class objects that contain objects of the derived class. Can you, please, check this out.

We are currently investigating these object binding issues and will keep you posted on the topic.

Best wishes,
Veli
the Telerik team

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answered on 12 Oct 2012, 09:42 AM

Hi,
I have same problem. I am binding the grid with Parent class and on the Sort it it fails for the properties which belongs to Child class.
I have these classes
abstract class GridItem
{
public int Id { get; set; }
public string Name { get; set; }
public string Type { get; set; }
}
abstract class CustomGridItem : GridItem
{
public int StatusId { get; set; }
public string Description { get; set; }
}
class AGridItem : CustomGridItem
{
public string Height { get; set; }
public string Width { get; set; }
public string Color { get; set; }
}

ASPX.cs
protected void rgGridItems_NeedDataSource(object source, GridNeedDataSourceEventArgs e)
{
rgGridItems.DataSource = GetGridItems();
}
private IEnumerable<GridItem> GetGridItems()
{
// Implementation
}
I am binding RadGrid with a collection of GridItem type and the Grid has columns like Id, Name, Height, Width, Color defined at design time.
Radgrid is successfully showing data from all the fields/columns, but when I Sort on Height, it says "No property or field Height exists in Type GridItem ".

I have following questions:
1. If Height doesn't belong to GridItem, then why the first time data gets bound with RadGrid and successfully shows data in "Height" column.
2.why it is trying to find Property directly in GridItem, why not in any children.
Note: I have tried the property RetrieveDataTypeFromFirstItem="true/false" doesn't help.

3.I have tried the same solution by upgrading it to Telerik 2012 latest release, same bug exists.

Thanks

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Sorting problem with Inheritance

9 Answers, 1 is accepted