Question

I’m using C# and WebForms and running into an issue. I have a class like this:

 public class Foo
 {
      public int _touchID;
      public string _touchName;
  }

Then I have a Dao object that returns a Listof Foo and I want to bind that list to a DataGrid.

public List<Foo> getFooList()
    { //get my list and whatnot}

I bind it to my asp:DataGrid like this:

TouchGrid.DataSource = dao.getFooList();
TouchGrid.DataBind();

The aspx page is like this:

 <asp:DataGrid ID="TouchGrid" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundColumn HeaderText="ID" DataField="_touchID"></asp:BoundColumn>
        <asp:TemplateColumn HeaderText="Touch">
            <ItemTemplate>
                  <asp:Label ID="touchName" text='<%#DataBinder.Eval(Container.DataItem, "_touchname") %>' runat="server"/>
                  <%--<div class="touchDescriptionHidden"><%#DataBinder.Eval(Container.DataItem, "_description")%></div>--%>
            </ItemTemplate>
        </asp:TemplateColumn>
    </Columns>
</asp:DataGrid>

When I run the code, I get a runtime exception because

A field or property with the name ‘_touchID’ was not found on the
selected data source.

I’ve tried using DataItem._touchID but I got the same error using that. I also tried to autogenerate the columns to see if I could get some hint as to why this is failing but I get a message saying

Unable to autogenerate columns for selected datasource

I know I’m missing something but I’m not sure exactly what. If I debug on the DataBind line and look at the DataSource, I can see my objects just fine:

TouchGrid.DataSource

 [0] - _touchID=1 | _name="stuff"  
 [1] - _touchID=2 | _name="otherStuff" 

What is the problem here?

Answer 1

DataBinding mechanism does not work with class fields, but with class properties.

So you need to convert the fields to properties (also this a requested OOP principle).

public class Foo
 {
      public int _touchID;
      public string _touchName;
  }

becomes

public class Foo
 {
      public int TouchID {get; set;}
      public string TouchName {get; set;}
  }