Intersoft Community - WebGrid Enterprise - Client Binding Virtual Group Paging - Handle Join Tables

Client Binding Virtual Group Paging - Handle Join Tables

Glayaar — Tue, 12 Oct 2010 02:38:54 GMT

The only way I could make it work is by using this query

var datasource = from b in context.Bugs
				 join o in context.Owners on b.BugId equals o.BugId into tl_j

				 from j in tl_j.DefaultIfEmpty()
				 select new BugWithOwner
				 {
					  BugId = b.BugId,
					  ChangeInLast = b.ChangeInLast,
					  Component = b.Component,
					  Dupe = b.Dupe,
					  OpSys = b.OpSys,
					  Severity = b.Severity,
					  Summary = b.Summary,
					  Target = b.Target,
					  OwnerId = j == null ? -1 : j.OwnerId,
					  OwnerName = j == null ? "--" : j.OwnerName
				  };

Client Binding Virtual Group Paging - Handle Join Tables

dmcgoff — Mon, 11 Oct 2010 22:14:41 GMT

Hi Glenn,

That solved my issue with the join - thanks! I now have a follow up issue. I am using a left join, so some of the columns contain "Null" values. I attempted to use a default values class to replace the Nulls. Unfortunately, I am getting an error.

The attached sample shows the error.

Can you take a look?

Thanks,

Dave

Client Binding Virtual Group Paging - Handle Join Tables

Glayaar — Sun, 10 Oct 2010 22:52:59 GMT

Under such scenario, you will be required to create a new class to hold the new object. In my sample, I create a BugCustom class that will allow me to hold the new property. Here is the snippet:

Class definition

public class BugCustom
{
    public int BugId { get; set; }
    public string Summary { get; set; }
    public string OwnerName { get; set; }
}

Select function (I do not have the Owners table, the select is simulated to return row with 3 column)

[WebMethod]
public object GetPagedBugsCustom(DataSourceSelectArguments selectArguments)
{
    BugTrackerModelDataContext context = new BugTrackerModelDataContext();
    context.DeferredLoadingEnabled = false;

    var datasource2 = 
        from b in context.Bugs
        select new BugCustom { BugId = b.BugId, Summary = b.Summary, OwnerName = "TestOwner" };


    WebGridDataProvider<BugCustom> provider = new WebGridDataProvider<BugCustom>(datasource2.AsQueryable());
    object data = provider.Select(selectArguments);

    if (data != null)
        return data;

    throw new InvalidOperationException("Unsupported operation type!");
}

The WebGrid client binding setting property

<ClientBindingSettings DataLoadMode="PagedData" DataSourceType="WebService" PreloadGroupTotals="true"
    ItemTypeName="BugCustom" ServiceUrl="WebService.asmx" EnableGroupRowPaging="true" GroupRowPageSize="20">
    <ServiceMethods SelectMethod="GetPagedBugsCustom" />
</ClientBindingSettings>

Client Binding Virtual Group Paging - Handle Join Tables

dmcgoff — Fri, 08 Oct 2010 12:42:42 GMT

I am using the ClientBinding_VirtualGroupPaging_WebService Example. My scenario requires that I join 2 tables in order to get the necessary data for my grid.

With a single table I have no issues. When joining tables I am not sure of what object to use in the Provider declaration (basically how should I fill the "???" in: WebGridDataProvider<???>).

Below is my code for 1) Single table and 2) join.

[WebMethod]

public object GetPagedBugs(DataSourceSelectArguments selectArguments)

{

BugTrackerModelDataContext context = new BugTrackerModelDataContext();

context.DeferredLoadingEnabled = false;

// 1) Single table works great

var datasource = from b in context.Bugs

select b;

WebGridDataProvider<Bug> provider =

new WebGridDataProvider<Bug>(datasource);

// -----------------------------------------

// 2) How to join?

var datasource2 = from b in context.Bugs

join o in context.Owners on b.BugId = o.BugId

select new { b.BugId, b.Summary, o.OwnerName };

WebGridDataProvider<???> provider =

new WebGridDataProvider<???>(datasource);

// -----------------------------------------

object data = provider.Select(selectArguments);

if (data != null)

return data;

throw new InvalidOperationException("Unsupported operation type!");

}