In my opinion, your scenario can be achieved by integrating WebInput into WebGrid.

By doing so, you can utilize the features of WebInput such as formatting display text; formatting edit text; input highlight; and masking. This sample of WebInput demonstrates WebInput control with numeric display format. Try to alter the culture by selecting it from the drop down list located on the top-right corner of the sample.

Edited on October 20, 2016 1:08 AM
Reason: add information about built-in feature in WebGrid

WebGrid supports .NET built-in masking, such as "c" for currency, "d" for short date, custom pattern such as "MM/dd/yyy" and so on. When the edit mode is activated, it will check the assigned DataFormatString and apply it to the built-in validation core function for data checking and masking. In the sample, the DataFormatString property of UnitPrice column is set to "c" (currency).

WebGrid also has numeric formatting feature. You only need to fill DataFormatString property with the numeric format. In the sample, try to edit UnitPrice to 1234 and Discount to 0.35.

WebGrid also supports custom format string, such as 0, #, ., comma, #, E0, \, Literal as well as ;. For more detail, please check the sample in here.

Thank you Yudi, it is helpful.