Excel Get_Range with multiple areas

Try this:

using Excel = Microsoft.Office.Interop.Excel;

1. Collect your ranges into an array:

Excel.Range[] ranges = new Excel.Range[] {yourRange1, yourRange2, ... };

2. Create string-range with ranges addresses and get multi-range from it:

string multiRangeStr = "";
foreach (Excel.Range range in ranges)
{
    string address = range.Address[true, true, Excel.XlReferenceStyle.xlA1];
    multiRangeStr += (multiRangeStr == "" ? "" : ";") + address;
}
//output: multiRangeStr: "A1:A3;B1:B3"

Excel.Range multiRange = wsheet.Range(multiRangeStr);

A very simple solution is to specify different areas in comma-separated form:

sheet.get_Range( "A1:B1,E1:G1");

For programmatic range combinations, there are also the Union and Intersection methods of the ExcelApplication object. Those are a little bit clumsy to use in C# because of many optional parameters. See here

http://codeidol.com/csharp/c-sharp-in-office/Working-with-Excel-Objects/Working-with-the-Range-Object/

for examples.

EDIT: some additional hints:

In your case, you first should transform the "ColumnsToSkip" in "ColumnsToKeep", since that is what you will need for any kind of cell union. Here is a Linq solution:

int[] ColumnsToKeep = Enumerable.Range(StartColumn, EndColumn -StartColumn + 1)
                      .Except(ColumnsToSkip)
                      .ToArray();

Then, you can create something along the lines of this example:

   Excel.Range totalRange = null;
   foreach(int col in ColumnsToKeep)
   {
        totalRange = Union(excelApp,totalRange,(Excel.Range)sh.Cells[row, col]);
   }

where "Union" is defined, for example, like this:

    static Excel.Range Union(Excel.Application app, Excel.Range r1, Excel.Range r2)
    {
        if (r1 == null && r2 == null)
            return null;
        if (r1 == null)
            return r2;
        if (r2 == null)
            return r1;
        return  app.Union(r1, r2,
            null, null, null, null, null, null,
            null, null, null, null, null, null,
            null, null, null, null, null, null,
            null, null, null, null, null, null,
            null, null, null, null);
    }