Using more than one Domain Data Source Control on a page

Question

User334174592 posted

Whenever I try to use more than one Domain Data Source control on a page I get an error:

An item with the same key has already been added.

[ArgumentException: An item with the same key has already been added.]
   System.ServiceModel.DomainServices.Server.DefaultDomainServiceFactory.CreateDomainService(Type domainServiceType, DomainServiceContext context) +125
   Microsoft.Web.UI.WebControls.DomainDataSourceView.CreateDomainService(DomainOperationType operationType) +144
   Microsoft.Web.UI.WebControls.DomainDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +336
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +143
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +74
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +66
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +102
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496

Answer 1

User443262777 posted

I understand you can have multiple data contexts but you can't have the same entity defined more than once. Thank you

Answer 2

User334174592 posted

Thank you. You are correct. It appears to be a problem when trying to consume a Domain Data Source created by lightSwitch. After I read your post I tried with a normal project and it works as you describe.