Hi RakhiS,
Greetings from syncfusion support
From validating your query, we understand you want to show the dropdown column in the dialogue Grid. We have already discussed your requirement in our sample demos. Please refer the below demo for more information.
And also from validating your query, we understand that you want to bind the external datasource for the dropdown column which was not exist in the Grid datasource. So we suspect that you want to show the dropdown datasource like our foreign column. Please refer the below sample demo for more information.
And then we suspect you want to bind the custom the custom datasource like the below screenshot. In this below screenshot, we have maintained three datasource in the Grid. While editing the dialog we have displayed the additional dropdown data. So please confirm if you want same as the below screenshot. Please refer the below screenshot for more information.
Screenshot:
If we misunderstood your query please get back to us with grid code example and provide more details regarding the requirement.
Regards,
Rajapandi R