将Dataset导出到Excel

还是朋友让我写的那个程序昨天刚解决了导入，并做好了筛选、排序、添加、删除、查找、替换之类的，现在要做导出了。通过网友解答和查资料，实现了导出：
代码如下：
先得引用Excel组件。
其中，mydata是我的Dataset信息。对信息进行逐行填充，最后输出。

  Try
            Dim selEmployeeContract As String = "Select   *   from   *   "
            Dim dsEmployeeContract As DataSet = New DataSet
            dsEmployeeContract = mydata
            If dsEmployeeContract Is Nothing Then
                MsgBox("没有数据，无法导出！", MsgBoxStyle.OkOnly)
                Exit Sub
            Else
                Dim xlsapp As New Excel.Application
                xlsapp.Workbooks.Add()
                xlsapp.Visible = True
                xlsapp.Selection.Merge()

                Dim i As Int16
                For i = 1 To dsEmployeeContract.Tables(0).Columns.Count
                    xlsapp.Cells(1, i) = dsEmployeeContract.Tables(0).Columns(i - 1).ColumnName
                Next
                Dim rowindex As Integer = 2
                Dim colindex As Integer
                Dim col As DataColumn
                Dim row As DataRow
                Dim nxh As Integer = 1
                For Each row In dsEmployeeContract.Tables(0).Rows
                    colindex = 1
                    For Each col In dsEmployeeContract.Tables(0).Columns
                        If colindex = 1 Then
                            xlsapp.Cells(rowindex, colindex) = RTrim(Convert.ToString(row(col.ColumnName)))
                        Else
                            xlsapp.Cells(rowindex, colindex) = RTrim(Convert.ToString(row(col.ColumnName)))
                        End If
                        colindex += 1
                    Next
                    rowindex += 1
                    nxh += 1
                Next
                xlsapp.Range(xlsapp.Cells(2, 1), xlsapp.Cells(dsEmployeeContract.Tables(0).Rows.Count + 2, dsEmployeeContract.Tables(0).Columns.Count)).Font.Size = 9
                xlsapp.Range(xlsapp.Cells(2, 6), xlsapp.Cells(dsEmployeeContract.Tables(0).Rows.Count + 2, 4)).NumberFormat = "yyyy-MM-dd"
                xlsapp.Range(xlsapp.Cells(2, 7), xlsapp.Cells(dsEmployeeContract.Tables(0).Rows.Count + 2, 5)).NumberFormat = "yyyy-MM-dd"
                xlsapp.Columns.AutoFit()
            End If
        Catch ex As Exception
            MsgBox(ex.ToString(), MsgBoxStyle.Critical)
        End Try