asp.net生成excel文件的类

  asp.net生成excel文件的类    调用:Dim clsExcel As New clsCommonExcel2
    clsExcel.createAndDowloadExcel(table, "sheet名称", "生成的excel名称", "1,3,5", 20000)
    Imports Interop
    Imports System.Web.HttpServerUtility
    Imports Interop.Excel.Constants
    Imports Interop.Excel.XlPasteType
    Imports Interop.Excel.XlBordersIndex
    Imports Interop.Excel.XlLineStyle
    Imports Interop.Excel.XlBorderWeight
    Imports Interop.Excel.XlUnderlineStyle
    Public Class clsCommonExcel2
    Inherits System.Web.UI.Page
    ''' <summary>
    ''' web服务器端生成excel文件
    ''' </summary>
    ''' <param name="table">数据集DataTable</param>
    ''' <param name="sheetName">excel的sheet名称</param>
    ''' <param name="newFileName">excel文件名称</param>
    ''' <param name="txtFormat">第1,3,5列要设为文本格式,则传入[1,3,5]</param>
    ''' <param name="cntPerSheet">每sheet的数据件数,超过则新生成sheet</param>
    ''' <remarks></remarks>
    Public Sub createAndDowloadExcel(ByVal table As DataTable, ByVal sheetName As String, _
    ByVal newFileName As String, ByVal txtFormat As String, _
    ByVal cntPerSheet As Integer)
    createExcelFile(table, sheetName, newFileName, txtFormat, cntPerSheet)
    '回收进程
    GC.Collect()
    End Sub
    Protected Sub createExcelFile(ByVal table As DataTable, ByVal sheetName As String, _
    ByVal newFileName As String, ByVal txtFormat As String, _
    ByVal cntPerSheet As Integer)
    Dim app As Excel.Application
    Dim workbook As Excel.Workbook
    Dim worksheet As Excel.Worksheet
    Dim arr(,) As Object
    Dim cntSheet As Integer
    Dim m As Integer
    ''删除既存文件
    'System.IO.File.Delete(Server.MapPath("//DownLoadFile/" + newFileName))
    app = New Excel.Application
    app.Visible = False
    workbook = app.Workbooks.Add(1)
    app.DisplayAlerts = False
    workbook.SaveAs(Server.MapPath("//DownLoadFile/" + newFileName))
    '计算sheet数
    If table.Rows.Count Mod cntPerSheet = 0 Then
    cntSheet = table.Rows.Count / cntPerSheet
    Else
    cntSheet = Int(table.Rows.Count / cntPerSheet) + 1
    End If
    For k = 0 To cntSheet - 1
    ReDim arr(cntPerSheet, table.Columns.Count - 1)
    For j As Integer = 0 To table.Columns.Count - 1
    arr(0, j) = table.Columns(j)。ColumnName
    Next
    workbook.Sheets(workbook.Sheets.Count)。Select()
    worksheet = workbook.Sheets.Add()
    worksheet.Name = sheetName + "_" + (k + 1)。ToString
    m = 1
    For i As Integer = k * cntPerSheet To (k + 1) * cntPerSheet - 1
    If i < table.Rows.Count Then
    For j As Integer = 0 To table.Columns.Count - 1
    'arr(m, j) = table.Rows(i)。Item(j)  防止excel单元格中信息以”-,=“开头
    If Not IsNumeric(table.Rows(i)。Item(j)) AndAlso table.Rows(i)。Item(j)。ToString.Length > 1 AndAlso _
    (Left(table.Rows(i)。Item(j)。ToString, 1)。Equals("-") OrElse Left(table.Rows(i)。Item(j)。ToString, 1)。Equals("=")) Then
    arr(m, j) = "'" + table.Rows(i)。Item(j)
    Else
    arr(m, j) = table.Rows(i)。Item(j)
    End If
    Next
    m = m + 1
    End If
    Next
    '格式
    With worksheet
    .Cells.Select()
    With app.Selection.Font
    .Name = "宋体"
    .Size = 11
    .Strikethrough = False
    .Superscript = False
    .Subscript = False
    .OutlineFont = False
    .Shadow = False
    .Underline = xlUnderlineStyleNone
    .ColorIndex = xlAutomatic
    End With
    .Range("A1:" + num2letter(worksheet, table.Columns.Count) + "1")。Select()
    With app.Selection.Interior
    .ColorIndex = 6
    .Pattern = xlSolid
    End With
    app.Selection.Font.Bold = True
    With app.Selection
    .HorizontalAlignment = xlCenter
    .VerticalAlignment = xlCenter
    .WrapText = False
    .Orientation = 0
    .AddIndent = False
    .IndentLevel = 0
    .ShrinkToFit = False
    .ReadingOrder = xlContext
    .MergeCells = False
    End With
    Dim arrInx() As String = txtFormat.Split(",")
    For i As Integer = 0 To arrInx.Length - 1
    '设置文本格式
    .Columns(num2letter(worksheet, CInt(arrInx(i))) + ":" + num2letter(worksheet, CInt(arrInx(i))))。Select()
    app.Selection.NumberFormatLocal = "@"
    Next
    worksheet.Range("A1")。Resize(cntPerSheet + 1, table.Columns.Count)。Value = arr
    .Columns("A:" + num2letter(worksheet, table.Columns.Count))。Select()
    .Columns("A:" + num2letter(worksheet, table.Columns.Count))。EntireColumn.AutoFit()
    End With
    worksheet.Range("A1")。Select()
    Next
    workbook.Sheets(workbook.Sheets.Count)。Select()
    app.ActiveWindow.SelectedSheets.Delete()
    workbook.Sheets(1)。Select()
    app.DisplayAlerts = False
    workbook.Save()
    workbook.Close()  'add 2011.11.1
    app.Quit()
    app = Nothing
    End Sub
    'n必须介于1到256之间
    Public Shared Function num2letter(ByVal worksheet As Excel.Worksheet, ByVal n As Integer) As String
    If n >= 1 And n <= 256 Then
    num2letter = IIf(n <= 26, Mid(worksheet.Cells(1, n)。Address, 2, 1), Mid(worksheet.Cells(1, n)。Address, 2, 2))
    Else
    num2letter = ""
    End If
    End Function
    End Class