尝试一下，代码是很容易解释的，但是如果您需要了解任何内容，请告诉我.

Try this, the code is pretty self explanatory, but if you need to understand anything let me know.

Option Explicit
Sub CopyPaste()

    Dim wb As Workbook, wbSource As Workbook, ws As Worksheet, wsSource As Worksheet 'variables for workbooks and sheets
    Dim LastRow As Long, LastCol As Integer 'variables for number rows and columns

    'To avoid selecting you must reference all the workbooks and sheets you are working on, and this is how:
    Set wb = ThisWorkbook 'this way you reference the workbook with the code
    Set ws = wb.Sheets("ChangeThis") 'name of the worksheet where you are going to pase
    Set wbSource = Workbooks.Open("C:\Users\xxx\Desktop\NewFolder\asal-gc.xlsx", UpdateLinks:=False, ReadOnly:=True) 'the source data workbook
    Set wsSource = wbSource.Sheets("Sheet1") 'the source data worksheet

    'Finding the range you want to copy
    With wsSource
        LastCol = .Cells(6, .Columns.Count).End(xlToLeft).Column 'this will get the last column on row 6, change that number if you need to
        LastRow = .Cells(.Rows.Count, LastCol).End(xlUp).Row 'this will get the last row on the last column, change the number of the col if there is more data on another column
        'this is taking the whole range from A1 to last col and row
        .Range("A1", .Cells(LastRow, LastCol)).Copy _
            Destination:=ws.Range("A1") 'this is where it will paste, if not range A1, change it wherever you need
    End With

    wbSource.Close Savechanges:=False 'this will close the source data workbook without saving

End Sub

此外，您不需要知道列字母，可以使用Cells(Row，Column)，它的索引编号为1 = A，2 = B，并且行等于该行的编号.

Also, you don't need to know the column letter, you can work with Cells(Row, Column) it works with their index number: 1 = A, 2 = B and for rows equals the number to the row.