GridView - How to use GridLookup in EditForm in multiple selection mode

Starting with v15.1, GridLookup can be automatically bound to a model field that returns an array of values (see  DevexpressEditorsBinder - Support binding multiple values selected in MVC editor extensions to a Model's collection-type property)
This example illustrates how to use GridLookup in a multiple selection mode (SelectionMode is Multiple) as a GridView editor. The main idea is to use the MVCxGridViewColumn.SetEditItemTemplateContent method to place GridLookup in EditForm. The same approach will work for a custom EditForm (GridViewSettings.SetEditFormTemplateContent) as well.

Note that prior to version 16.1.6, the GridLookupExtension.Bind method doesn't automatically select required keys. It's necessary to assign a delegate method to the PreRender property to manually select the values using the GridViewSelection.SelectRowByKey method. Starting with version 16.1.6, it is sufficient to pass values to bind/select to the GridLookupExtension.Bind method.

[C#]
//Prior to version 16.1.6 onlysettings.PreRender=(s,e)=>{MVCxGridLookuplookup=sasMVCxGridLookup;for(inti= 0;i<Model.TagIDs.Length;i++)lookup.GridView.Selection.SelectRowByKey(Model.TagIDs[i]);};

[VB.NET]
'Prior to version 16.1.6 only
 settings.PreRender = Sub(s, e)Dim lookup As MVCxGridLookup = TryCast(s, MVCxGridLookup)For i AsInteger = 0 To Model.TagIDs.Length - 1
                lookup.GridView.Selection.SelectRowByKey(Model.TagIDs(i))Next iEndSub

In order to use client-side unobtrusive JavaScript validation with GridLookup, it's necessary to pass a correct model instance to a partial view. This instance should be of the same type as an item of the collection bound to GridView.

Controller:

[C#]
publicActionResultGridLookupPartial(int?KeyParameter){varmodel=GetModelInstanceByKey(KeyParameter);returnPartialView(model);}

 

[VB.NET]
PublicFunction GridLookupPartial(ByVal KeyParameter?AsInteger) As ActionResultDim model = GetModelInstanceByKey(KeyParameter)Return PartialView(model)EndFunction

 PartialView:

[C#]
@Html.DevExpress().GridLookup(settings=>{settings.Name=PropertyName;}).BindList(...).Bind(Model.PropertyName).GetHtml()

[VB.NET]
@Html.DevExpress().GridLookup(Sub(settings)
    settings.Name = PropertyNameEndSub).BindList(...).Bind(Model.PropertyName).GetHtml()

See also: 
GridView - How to use GridLookup with single selection mode in EditForm

Web Forms:
How to use two-way data-bound ASPxGridLookup in edit form of ASPxGridView to edit data
How to use ASPxGridLookup in multiple selection mode as the ASPxGridView editor