When Setting the Initial DataSource Filter an Expected Primary Expression Exception Occurs

Environment

Product	Progress® Kendo UI® DataSource for ASP.NET MVC
Operating System	All
Visual Studio Version	All
View Engine	Razor

Description

The server returns an exception when it tries to load data from the DataSource by using the following filter configuration:

.DataSource(dataSource => dataSource
  .Ajax()
  .Filter(filter =>
  {
    filter.Add(p => p.Employee.Surname == "Korla");
    filter.Add(p => p.Status == false);
  })
  ...
)

Error Message

An Expected primaryExpression exception occurs.

[FilterParserException: Expected primaryExpression]
   Kendo.Mvc.Infrastructure.Implementation.FilterParser.PrimaryExpression() +381
   Kendo.Mvc.Infrastructure.Implementation.FilterParser.ComparisonExpression() +14
   Kendo.Mvc.Infrastructure.Implementation.FilterParser.OrExpression() +15
   Kendo.Mvc.Infrastructure.Implementation.FilterParser.Parse() +26
   Kendo.Mvc.Infrastructure.FilterDescriptorFactory.Create(String input) +63
   Kendo.Mvc.UI.DataSourceRequestModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) +213
   System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor) +337
   System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor) +105
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__19(AsyncCallback asyncCallback, Object asyncState) +743
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +14
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +128
   System.Web.Mvc.Async.AsyncControllerActionInvoker.BeginInvokeAction(ControllerContext controllerContext, String actionName, AsyncCallback callback, Object state) +343
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1c(AsyncCallback asyncCallback, Object asyncState, ExecuteCoreState innerState) +25
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +30
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +128
   System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state) +465
   System.Web.Mvc.Controller.<BeginExecute>b__14(AsyncCallback asyncCallback, Object callbackState, Controller controller) +18
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +20
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +128
   System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state) +374
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state) +16
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(AsyncCallback asyncCallback, Object asyncState, ProcessRequestState innerState) +52
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState) +30
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout) +128
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +384
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +48
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +103
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Cause

The Expected primaryExpression exception is frequently caused by the incorrect formatting of the filter expression.

Solution

Use the following syntax in the filter instead.

.DataSource(dataSource => dataSource
  .Ajax()
  .Filter(filter =>
  {
    filter.Add(p => p.Employee.Surname).IsEqualTo("Korla");
    filter.Add(p => p.Status).IsEqualTo(false);
  })
  ...
)