Thanks for using Syncfusion products.
The reported issue has occurred due to mismatching of DLL version in your sample. If you are using 220.127.116.11 and if the frame wok version is 4.0, then the DLL version should be 12.4400.0.24. Please check the ‘bin’ folder and refer the following table for DLL reference.
.Net Frame Work Version
Please follow the steps below:
1. Open the Syncfusion Essential Studio and click on Explore sample.
2. Click on samples and open web folder, you can get the bin folder inside.
3. Check the version of DLL inside the bin folder.
DLL version should match the framework version you have used. And also, please check the web.config file in your sample.
All the assemblies referred inside the web.config file should match your .NET framework version.
When the assemblies are referred from GAC reference, follow the provided steps.
1. Open Solution Explorer in the application, click on References and get the Syncfusion.EJ and Syncfusion.EJ.Web assembly references.
2. View the properties by right-clicking the Syncfusion.EJ.Web, inside references.
3. Check the version of the assembly in the Properties tab.
We have prepared the sample with basic Colorpicker component and it can be downloaded in the following location.
Also we are having a KB documentation regarding this error and it can found under the following link location.
Please let us know if you have further concern.
Thanks for your update.
We would like to let you know that, while installing our Essential Studio build all the assemblies will be placed in the following installed path location.
<Installed Location>\Syncfusion\Essential Studio\18.104.22.168\precompiledassemblies\22.214.171.124
In order to get 12.4400.0.24 Syncfusion.EJ.Web.dll you can find it in the following path location.
<Installed Location>\Syncfusion\Essential Studio\126.96.36.199\precompiledassemblies\188.8.131.52\4.0
Kindly check in the above installed location and refer the assembly in your sample. If still you can’f find the assemblies please report us back.
Please let us know if you have further queries.