c# - Write Array to Excel Range

Question

I'm currently trying to write data from an array of objects to a range in Excel using the following code, where objData is just an array of strings:

private object m = System.Type.Missing;
object[] objData = getDataIWantToWrite();

Range rn_Temp;
rn_Temp = (Range)XlApp.get_Range(RangeName, m);
rn_Temp = rn_Temp.get_Resize(objData.GetUpperBound(), 1);
rn_Temp.value2 = objData;

This very nearly works, the problem being that the range gets filled but every cell gets the value of the first item in the objData.

The inverse works, i.e.

private object m = System.Type.Missing;
object[] objData = new object[x,y]

Range rn_Temp;
rn_Temp = (Range)XlApp.get_Range(RangeName, m);
rn_Temp = rn_Temp.get_Resize(objData.GetUpperBound(), 1);
objData = (object[])rn_Temp.value2;

would return an array containing all of the values from the worksheet, so I'm not sure why reading and assignment work differently.

Has anyone ever done this successfully? I'm currently writing the array cell by cell, but it needs to cope with lots (>50,000) of rows and this is therefore very time consuming.

Answer 1

This is an excerpt from method of mine, which converts a DataTable (the dt variable) into an array and then writes the array into a Range on a worksheet (wsh var). You can also change the topRow variable to whatever row you want the array of strings to be placed at.

object[,] arr = new object[dt.Rows.Count, dt.Columns.Count];
for (int r = 0; r < dt.Rows.Count; r++)
{
    DataRow dr = dt.Rows[r];
    for (int c = 0; c < dt.Columns.Count; c++)
    {
        arr[r, c] = dr[c];
    }
}
Excel.Range c1 = (Excel.Range)wsh.Cells[topRow, 1];
Excel.Range c2 = (Excel.Range)wsh.Cells[topRow + dt.Rows.Count - 1, dt.Columns.Count];
Excel.Range range = wsh.get_Range(c1, c2);
range.Value = arr;

Of course you do not need to use an intermediate DataTable like I did, the code excerpt is just to demonstrate how an array can be written to worksheet in single call.