Blazor Multiselect Microsoft.JSInterop.JSException: Cannot read property 'DropDownBase' of undefined

[HappyCamper]

I am getting the following error quite randomly in the multiselect.  It would happen often, but not all the time I load my multiselect.  

Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer: Warning: Unhandled exception rendering component: Cannot read property 'DropDownBase' of undefined

TypeError: Cannot read property 'DropDownBase' of undefined

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:96522

    at Module../bundles/multiselect.js (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:112589)

    at s (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:110)

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:937

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:971

Microsoft.JSInterop.JSException: Cannot read property 'DropDownBase' of undefined

TypeError: Cannot read property 'DropDownBase' of undefined

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:96522

    at Module../bundles/multiselect.js (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:112589)

    at s (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:110)

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:937

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:971

   at Microsoft.JSInterop.JSRuntime.InvokeWithDefaultCancellation[T](String identifier, Object[] args)

   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)

   at Syncfusion.Blazor.Internal.SfBaseUtils.ImportScripts(IJSRuntime jsRuntime, String modulePath)

   at Syncfusion.Blazor.Internal.SfBaseUtils.ImportModules(IJSRuntime jsRuntime, List`1 scriptModules, String hashKey)

   at Syncfusion.Blazor.BaseComponent.InitComponent()

   at Syncfusion.Blazor.BaseComponent.OnAfterRenderAsync(Boolean firstRender)

   at Syncfusion.Blazor.DropDowns.SfMultiSelect`1.OnAfterRenderAsync(Boolean firstRender)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost: Error: Unhandled exception in circuit 'MnmziLUVnD-iWWCQWjfva07pd8Xwwz3-2xGvA4LFujI'.

Microsoft.JSInterop.JSException: Cannot read property 'DropDownBase' of undefined

TypeError: Cannot read property 'DropDownBase' of undefined

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:96522

    at Module../bundles/multiselect.js (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:112589)

    at s (https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:110)

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:937

    at https://localhost:44349/_content/Syncfusion.Blazor/scripts/multiselect-57fa2c.min.js:1:971

   at Microsoft.JSInterop.JSRuntime.InvokeWithDefaultCancellation[T](String identifier, Object[] args)

   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)

   at Syncfusion.Blazor.Internal.SfBaseUtils.ImportScripts(IJSRuntime jsRuntime, String modulePath)

   at Syncfusion.Blazor.Internal.SfBaseUtils.ImportModules(IJSRuntime jsRuntime, List`1 scriptModules, String hashKey)

   at Syncfusion.Blazor.BaseComponent.InitComponent()

   at Syncfusion.Blazor.BaseComponent.OnAfterRenderAsync(Boolean firstRender)

   at Syncfusion.Blazor.DropDowns.SfMultiSelect`1.OnAfterRenderAsync(Boolean firstRender)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

Any thoughts on what might be causing this?

[Ponmani Murugaiyan]

Hi HappyCamper,  

Thanks for contacting Syncfusion support.  

The cause for the script error “Cannot read property 'DropDownBase' of undefined” due to resources were not loaded properly also due to NuGet cache. So we suggest you to clear the NuGet by following the below link.    

 

NuGet clear KB  : https://www.syncfusion.com/kb/6987/how-to-clear-nuget-cache      

Also, we would like to let you know that, the static webassets will always be cached in the browser when we using Blazor WebAssembly application since the resources are loaded in the browser side for rendering.  So, we suggest you to set the HTTP header with no-cache option in your server configuration to resolve this problem. Please refer to the below Github thread and ASP.NET forum for more details.    

     

https://github.com/dotnet/aspnetcore/issues/20408      

     

https://forums.asp.net/t/2134899.aspx?How+to+set+no+cache+in+http+header+via+web+server+configuration+instead+of+code+change+and+its+running+cycle       

Please let us know if you need any further assistance on this.  

Regards,  

Ponmani M