知识大全在Asp.net用C#建立动态Excel

Posted 2022-07-17 权限

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　　在中建立本地的excel表并由服务器向外传播是容易实现的而删除掉嵌入的excel exe进程是困难的所以你不要打开任务管理器看Excel exe进程相关的东西是否还在内存里面我在这里提供一个解决方案里面提供了两个方法 CreateExcelWorkbook (说明建立Excel工作簿) 这个方法运行一个存储过程返回一个DataReader 并根据DataReader 来生成一个Excel工作簿并保存到文件系统中创建一个 download 连接这样用户就可以将Excel表导入到浏览器中也可以直接下载到机器上

　　第二个方法 generatecsvreport 本质上是做同样的一件事情仅仅是保存的文件的CSV格式仍然导入到Excel中 CSV代码能解决一个开发中的普片的问题你有一列里面倒入了多个零 CSV代码能保证零不变空（说明就是在Excel表中多个零的值不能保存的问题）

　　在可以下载的解决方案中包含一个有效的类 SPGen 能运行存储过程并返回DataReader 一个移除文件的方法能删除早先于一个特定的时间值下面出现的主要的方法就是CreateExcelWorkbook

　　注意你必须知道在运行这个页面的时候你可能需要能在WebSever 服务器的文件系统中写 Excel Csv文件的管理员的权限处理这个问题的最简单的方法就是运行这个页面在自己的文件夹里面并包括自己的配置文件并在配置文件中添加下面的元素

　　特别注意下面的代码块的作用是清除Excel的对象。

　　// Need all following code to clean up and extingush all references!!!oWB.Close(null,null,null);oXL.Workbooks.Close();oXL.Quit();System.Runtime.InteropServices.Marshal.ReleaseComObject (oRng);System.Runtime.InteropServices.Marshal.ReleaseComObject (oXL);System.Runtime.InteropServices.Marshal.ReleaseComObject (oSheet);System.Runtime.InteropServices.Marshal.ReleaseComObject (oWB);oSheet=null;oWB=null;oXL = null;GC.Collect(); // force final cleanup!

　　这是必须的，因为oSheet", "oWb" , \'oRng", 等等对象也是的实例，我们需要

　　marshal类的releaseobject的方法把它们去掉

　　private void CreateExcelWorkbook(string spName, SqlParameter[] parms)string strCurrentDir = Server.MapPath(".") + "\\\\";RemoveFiles(strCurrentDir); // utility method to clean up old files Excel.Application oXL;Excel._Workbook oWB;Excel._Worksheet oSheet;Excel.Range oRng;

　　tryGC.Collect();// clean up any other excel guys hangin\' around...oXL = new Excel.Application();oXL.Visible = false;//Get a new workbook.oWB = (Excel._Workbook)(oXL.Workbooks.Add( Missing.Value ));oSheet = (Excel._Worksheet)oWB.ActiveSheet;//get our Data

　　string strConnect = System.Configuration.ConfigurationSettings.AppSettings["connectString"];SPGen sg = new SPGen(strConnect,spName,parms); SqlDataReader myReader = sg.RunReader(); // Create Header and sheet...int iRow =2; for(int j=0;j oSheet.Cells[1, j+1] = myReader.GetName(j).ToString(); // build the sheet contentswhile (myReader.Read()) for(int k=0;k < myReader.FieldCount;k++)oSheet.Cells[iRow,k+1]= myReader.GetValue(k).ToString();iRow++;// end whilemyReader.Close();myReader=null;//Format A1:Z1 as bold, vertical alignment = center.oSheet.get_Range("A1", "Z1").Font.Bold = true;oSheet.get_Range("A1", "Z1").VerticalAlignment =Excel.XlVAlign.xlVAlignCenter;//AutoFit columns A:Z.oRng = oSheet.get_Range("A1", "Z1");oRng.EntireColumn.AutoFit();oXL.Visible = false;oXL.UserControl = false;string strFile ="report" + System.DateTime.Now.Ticks.ToString() +".xls";oWB.SaveAs( strCurrentDir + strFile,Excel.XlFileFormat.xlWorkbookNormal, null,null,false,false,Excel.XlSaveAsAccessMode.xlShared,false,false,null,null,null);// Need all following code to clean up and extingush all references!!!oWB.Close(null,null,null);oXL.Workbooks.Close();oXL.Quit();System.Runtime.InteropServices.Marshal.ReleaseComObject (oRng);System.Runtime.InteropServices.Marshal.ReleaseComObject (oXL);System.Runtime.InteropServices.Marshal.ReleaseComObject (oSheet);System.Runtime.InteropServices.Marshal.ReleaseComObject (oWB);oSheet=null;oWB=null;oXL = null;GC.Collect(); // force final cleanup!string strMachineName = Request.ServerVariables["SERVER_NAME"];errLabel.Text="

　　catch( Exception theException ) String errorMessage;errorMessage = "Error: ";errorMessage = String.Concat( errorMessage, theException.Message );errorMessage = String.Concat( errorMessage, " Line: " );errorMessage = String.Concat( errorMessage, theException.Source ); errLabel.Text= errorMessage ;

　　下面是原文章

　　create Dynamic ASP.NET Excel Workbooks In C#

　　by Peter A. Bromberg, Ph.D.Printer - Friendly Version

　　there is also, in the downloadable solution, a utility class "SPGen" that handles running stored

　　generating native Excel spreadsheets from your web server is not that difficult with ASP.NET. What can be difficult is making instances of Excel.exe go away so you don\'t open up TaskMgr and see 123 instances of EXCEL.EXE still sitting in memory. I provide here a solution that has o methods, "CreateExcelWorkbook", which runs a stored proceduire that returns a DataReader and assembles a native Excel Workbook from it, saves it to the filesystem, and creates a "Download" link so the user can either load the report into Excel in their browser, or download the XLS file. The second method, GenerateCSVReport, does essentially the same thing but creates a CSV file that will, of course, also load into Excel. The CSV code correctly handles a mon developer problem in that if you have a column that has leading zeroes, they are preserved.

　　procedures and returning DataReaders, and a RemoveFiles utility method that cleans up any XLS or CSV file older than the specified number of minutes. The key method presented below is the CreateExcelWorkbook method.

　　note: You should be aware that you will probably need to run this page under an account that has administrative privileges as it needs write permissions to store the generated Excel or CSV files on the webserver\'s file system. Probably the easiest way to handle this is to have the page in its own folder with its own nfig, and insert an

　　note especially the code block that does the "cleanup" of the Excel objects:

　　this is necessary because all those littlle objects "oSheet", "oWb" , \'oRng", etc. are all instances and we need to use the InteropServices ReleaseComObject method of the Marshal class to get rid of them in .NET.

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知识大全 在Asp.net用C#建立动态Excel

知识大全在Asp.net用C#建立动态Excel