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Webcontrol as a property of another webcontrol

Answer 1

+1 A:

this.FindControl()

http://msdn.microsoft.com/en-us/library/system.web.ui.control.findcontrol(v=VS.80).aspx

cRichter 2010-07-28 11:18:12

The FindControl only looks in any given container. But if this the only tool available for this situation, then the solution is to build a recursive method that traverses the page structure and return the control that matches the id provided.

SynBiotik 2010-07-28 14:39:29

hmm... but isn't Page.FindControl() searching on the whole page?

cRichter 2010-07-29 09:07:52

It's not supposed to:"The FindControl method can be used to access a control whose ID is not available at design time. The method searches only the page's immediate, or top-level, container; it does not recursively search for controls in naming containers contained on the page. To access controls in a subordinate naming container, call the FindControl method of that container." - http://msdn.microsoft.com/en-us/library/31hxzsdw.aspx

SynBiotik 2010-07-29 13:15:52

Answer 2

A:

Here's a sample of a GridView bound to an ObjectDataSource, with the ObjectDataSource binding to a DropDownList for a parameter. This should get you started.

<asp:GridView ID="GridView1" runat="server" 
    AutoGenerateColumns="False" 
    DataSourceID="CustomerObjectDataSource" 
    DataKeyNames="CustomerID"
    AllowPaging="True" 
    AllowSorting="True" AutoGenerateDeleteButton="True" 
    AutoGenerateEditButton="True" AutoGenerateSelectButton="True" 
    onrowdeleted="GridView1_RowDeleted" onrowupdated="GridView1_RowUpdated">
    <Columns>
        ...
    </Columns>
</asp:GridView>

<asp:ObjectDataSource ID="CustomerObjectDataSource" runat="server" 
    EnablePaging="True" 
    MaximumRowsParameterName="totalRows" 
    StartRowIndexParameterName="firstRow" 
    TypeName="Northwind.Business.CustomerSource" 
    DataObjectTypeName="Northwind.Business.CustomerDTO"
    SelectMethod="Load" 
    UpdateMethod="Save" 
    InsertMethod="Insert" 
    DeleteMethod="Delete"
    SelectCountMethod="CustomerCount" 
    SortParameterName="sortExpression">
    <SelectParameters>
        <asp:ControlParameter ControlID="ddlRegion" Name="region" 
            PropertyName="SelectedValue" />
    </SelectParameters>
</asp:ObjectDataSource>

Cylon Cat 2010-07-28 11:23:18

The question that remains is: Does the gridview locate the ObjectDataSource by traversing the page recursively using the FindControl method?

SynBiotik 2010-07-28 14:40:17

@SynBiotik, no. The DataSourceID field of the GridView markup identifies the ObjectDataSource by the data source's ID. The binding is explicit (in the example code above, "CustomerObjectDataSource").

Cylon Cat 2010-07-28 19:52:57

IHere is the DataSourceId code:public virtual string DataSourceID{ get { object obj2 = this.ViewState["DataSourceID"]; if (obj2 != null) { return (string) obj2; } return string.Empty; } set { if (string.IsNullOrEmpty(value) } this.ViewState["DataSourceID"] = value; this.OnDataPropertyChanged(); }}How does the gridview tie the string to the actual object ?

SynBiotik 2010-07-29 10:55:16

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Webcontrol as a property of another webcontrol

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