Hi Emperor,
You can use sheet.Range[row,column,lastrow,lastcol].Merge() to merge 5 columns within the same row and instead of using column+5 you can use lastcol+1 to insert text. Please refer the following code snippet which illustrates the above:
[C#]
int row=1;
int column=1;
int lastrow=1;
int lastcol=5;
// Merging cells (5 columns)
sheet.Range[row,column,lastrow,lastcol].Merge();
//Insert data
sheet.Range[row,lastcol+1].Text="Inserted Successfully";
Please refer the following sample which implements the above said feature:
MergeCels.zipKindly take a look and let me know if it meets your need.
Thanks,
Melba