I am using ExcelDNA to set and get cell values. I can get and set cell values
var ref = ExcelReference(2, 2);
var val = ref.GetValue();
I'd recommend using the COM object model for this, and the code will be similar to VBA for the same task.
You get hold of the root
Application object with a call to
ExcelDnaUtil.Application. The resulting object will be of type
Microsoft.Office.Interop.Excel.Application and can be used to select the row of column, then call
app.Selection.Insert() to insert the new row or column.
It should also be possible using the C API, but that is unlikely to be easier or faster.