how to convert vb.net code to c#

Sub SentencesToExcel() 
    Dim appXL As Excel.Application 
    Dim wbkXLSource As Excel.Workbook 
    Dim wbkXLNew As Excel.Workbook 
     
    Dim strSearch() As String 
    Dim var 
    Dim r As Word.Range 
    Dim j As Long 
     
    Set appXL = CreateObject("Excel.Application") 
    Set wbkXLSource = appXL.Workbooks.Open(FileName:="c:\ZZZ\Test\test2\WordList.xls") 
    Set wbkXLNew = appXL.Workbooks.Add 
     
    For var = 0 To 2 
         ' build the array of search words from the source Excel file
        ReDim Preserve strSearch(var) 
        strSearch(var) = wbkXLSource.Worksheets("Sheet1").Cells(var + 1, 1).Value 
    Next 
     ' close the source Excel file as do not need it
    wbkXLSource.Close 
     ' destroy its object
    Set wbkXLSource = Nothing 
    j = 1 
     ' for each search words
    For var = 0 To UBound(strSearch()) 
         ' make a range ovbject of the whole document
        Set r = ActiveDocument.Range 
        With r.Find 
             ' with each Found
            Do While .Execute(Findtext:=strSearch(var), Forward:=True) _ 
                = True 
                 ' expand to the sentence
                r.Expand Unit:=wdSentence 
                 ' and put in the next cell in the new Excel file
                wbkXLNew.Worksheets("Sheet1").Cells(j, 1).Value = r.Text 
                j = j + 1 
                r.Collapse 0 
            Loop 
        End With 
    Next 
    appXL.Visible = True 
     
     'wbkXLNew.SaveAs FileName:="valid_path"
     'Set wbkXLNew = Nothing
     'appXL.Quit
     'Set appXL = Nothing
End Sub