I created a basic page with a webgrid on it. Created the four columns I care about (for now)
Column1 | Column2 | Column3 | Column4
I then create my datatype with the information for the columns, set it to the datasource, and bind that to the grid.
Then when I run the app, I get double the columns,
Column1 | Column2 | Column3 | Column4|Column1 | Column2 | Column3 | Column4
All columns have the information from placed in the data type. the datatype looks correct, Any idea what is going on here?
The grid is automatically generating columns for you, above and beyond the columns you've manually defined.
Either set the DisplayLayout.AutoGenerateColumns property of your grid to false, or set the IsBound property of each of your manually-defined columns to true.
Since you mention that you've "[c]reated the four columns [you] care about (for now)" I suspect that setting AutoGenerateColumns to false is likely what you're after.