不能为DataGrid1控件的单元个付值？？？？？

Set con = New ADODB.Connection
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.3.51;data source =" & App.Path & "..\db\afu.mdb"
con.Open
Set rs = New ADODB.Recordset

rs.Open "SELECT format (order.date,'yyyy-mm-dd') AS 送货时间, " & _
"order.amount AS 送出数量, " & _
"callback.amount AS 收回数量, " & _
"callback.shatter AS 损坏数量, " & _
"[order].[amount]-[callback].[amount]-[callback].[shatter] AS 在途数量 " & _
"FROM [order] left JOIN callback ON order.date = callback.reclaim_date " & _
"WHERE order.date < #" & DTPicker1.Value & "# AND " & _
"order.customerName='詹樱楼' And " & _
"order.breedName='五件套'", con, adOpenStatic, adLockOptimistic, vbServer
Set DataGrid1.DataSource = rs
a = 0
b = 0
c = 0
d = 0
e = 0

For a = 1 To rs.RecordCount
If IsNull(rs!在途数量) Then
b = 0
Else
b = rs!在途数量
End If
If IsNull(rs!收回数量) Then
c = 0
Else
c = rs!rs!收回数量
End If
If IsNull(rs!损坏数量) Then
d = 0
Else
d = rs!损坏数量
End If

DataGrid1.Row = a
DataGrid1.Col = 4
‘ DataGrid1.Columns(4).Text = "ccccccc"
DataGrid1.Text = b - c - d + e
e = b - c - d + e
rs.MoveNext
Next
现在执行到DataGrid1.Text = b - c - d + e是报错“数据访问错误”
但是执行到DataGrid1.Columns(4).Text = "ccccccc"又报错“类型不匹配”
各位老师帮帮我吧！！！！！