Is it possible to use the Edit command API to dynamically change the cell content to my own custom editor?  I would like my datagrid to look like everything is a text cell, but when I double click a cell, I want a custom editor control to appear as the cell content instead.  The user then uses the custom editor control to change the value, and then when he commits the edit, the dynamic custom editor control disappears and I see the text cell again, but with the new value.  I think this is how the normal editing commands work on the data grid, but I want to use my own custom editors instead of the default ones.

Hello Shawn,

With the current implementation of the control changing the default editor of the Column when edit mode is entered in not supported. I have logged this in our Feedback portal on your behalf and you can follow it in order to receive notifications on status changes at the link below:
https://feedback.telerik.com/xamarin/1386862-datagrid-provide-a-functionality-for-changing-the-default-editor-of-the-typed-columns​

I am afraid that due to the specificity of the implementation of the control, currently I cannot suggest you any suitable solution that you can use in order to achieve the desired functionality. I have updated your Telerik points for bringing this to our attention.

If you have any additional questions or concerns, please let me know. 

Regards,
Nasko
Progress Telerik