The connection point “filter parameter” on does not allow multiple connections

Question

I have a custom web part which does not allow multiple connection. Scenario : i add the custom web part on the page , add 2 list on the same page .

Step 1 : I connect List 1 to web part and implement my functionality. Step 2 : I delete List1. Step 3 : I get my custom error message that list name is invalid.[As required for the functionality] Step 4 : I edit web part , and try to connect it to List 2. Step 5 : Error message received "The connection point "filter parameter" on "g_789a749a_836c_45c4_b247_f4bfa28b94a3" does not allow multiple connections. "


Stack Trace WebPartPageUserException: The connection point "filter parameter" on "g_789a749a_836c_45c4_b247_f4bfa28b94a3" does not allow multiple connections.]<br/> Microsoft.SharePoint.WebPartPages.SPWebPartManager.CanSPConnectWebPartsCore(WebPart provider, ProviderConnectionPoint providerConnectionPoint, WebPart consumer, ConsumerConnectionPoint consumerConnectionPoint, WebPartTransformer transformer, Boolean throwOnError) +2369<br/> Microsoft.SharePoint.WebPartPages.SPWebPartManager.SPConnectWebParts(WebPart provider, ProviderConnectionPoint providerConnectionPoint, WebPart consumer, ConsumerConnectionPoint consumerConnectionPoint, WebPartTransformer transformer, Boolean bCheck) +96<br/> Microsoft.SharePoint.WebPartPages.Communication.PersistConnection.CreateConnection(String xFormTypeName, String xFormInfo) +630<br/> Microsoft.SharePoint.WebPartPages.Communication.PersistConnection..ctor(ConnectionDesigner designer, SPWebPartManager manager) +1517<br/> Microsoft.SharePoint.WebPartPages.Communication.ConnectionDesigner.PersistChangedConnections() +63<br/> Microsoft.SharePoint.WebPartPages.SPWebPartManager.CreateConnectionDesigner() +437<br/> Microsoft.SharePoint.WebPartPages.SPWebPartManager.ActivateConnections() +361<br/> System.Web.UI.WebControls.WebParts.WebPartManager.OnPageLoadComplete(Object sender, EventArgs e) +70<br/> System.EventHandler.Invoke(Object sender, EventArgs e) +0<br/> System.Web.UI.Page.OnLoadComplete(EventArgs e) +11046222<br/> System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3160<br/>

i am think of checking weather the web part has any connection or could be connected to the list.
Can anyone help me in implementing this.

Answer 1

I fixed it by adding AllowsMultipleConnections:

[ConnectionConsumer("Filter", "UniqueFilterName", AllowsMultipleConnections = true)]
public void GetConnectionInterface(IWebPartParameters pProvider)
{
}