C#生成Excel另辟蹊径的方法
想用c#生成excel，在网上搜一下，大多都是借助GridView，其实这种生成方式，生成的文件，根本就不是真正的Excel，而是html。
如果数字超过15位的话，会转化成科学计数法，就不准确了。
用com组件的话，也行，就是不太好用，速度还慢。
第三方类库ExcelLibrary，确实不错，但是它是gpl协议，还是舍弃了。
下面介绍一个另辟蹊径的方法。这个方法是借助LocalReport实现的。
导出的是真正的Excel文件，数据准确，如果数字长度尝过15位，自动转换成字符串。
其原理是动态的生成.rdlc本地报表文件，然后通过它生成excel文件。本地报表也可以生成pfd等其他文件。
下面是代码，出自我的开源项目，http://lmcommon.codeplex.com/
写的比较粗糙，仅供参考吧，不过还能用。
View Code
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Windows.Forms; using System.Data; namespace Lm.Common.Excel { public class ExcelBuilder { protected DataTable dataTable { get; set; } public ExcelBuilder(DataTable dt) { this.dataTable = dt; } protected string GenerateRdlc() { StringBuilder sb = new StringBuilder(); sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>"); sb.Append("<Report xmlns:rd=\"http://schemas.microsoft.com/SQLServer/reporting/reportdesigner\" xmlns=\"http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition\">"); sb.Append("<DataSources>"); sb.Append("<DataSource Name=\"DataSet1\">"); sb.Append("<ConnectionProperties>"); sb.Append("<DataProvider>System.Data.DataSet</DataProvider>"); sb.Append("<ConnectString>/* Local Connection */</ConnectString>"); sb.Append("</ConnectionProperties>"); sb.Append("<rd:DataSourceID>" + Guid.NewGuid().ToString() + "</rd:DataSourceID>"); sb.Append("</DataSource>"); sb.Append("</DataSources>"); sb.Append("<DataSets>"); sb.Append("<DataSet Name=\"DataSet1\">"); sb.Append("<Fields>"); for (var i = 0; i < this.dataTable.Columns.Count; i++) { var c = this.dataTable.Columns[i]; sb.Append("<Field Name=\"" + c.ColumnName + "\">"); sb.Append("<DataField>" + c.ColumnName + "</DataField>"); sb.Append("<rd:TypeName>" + c.DataType.ToString() + "</rd:TypeName>"); sb.Append("</Field>"); } sb.Append("</Fields>"); sb.Append("<Query>"); sb.Append("<DataSourceName>DataSet1</DataSourceName>"); sb.Append("<CommandText>/* Local Query */</CommandText>"); sb.Append("</Query>"); //sb.Append("<rd:DataSetInfo>"); //sb.Append("<rd:DataSetName>wmsTestDataSet</rd:DataSetName>"); //sb.Append(@"<rd:SchemaPath>D:\我的文档\桌面\TestApp\rdlcTest\wmsTestDataSet.xsd</rd:SchemaPath>"); //sb.Append("<rd:TableName>BNK</rd:TableName>"); //sb.Append("<rd:TableAdapterFillMethod>Fill</rd:TableAdapterFillMethod>"); //sb.Append("<rd:TableAdapterGetDataMethod>GetData</rd:TableAdapterGetDataMethod>"); //sb.Append("<rd:TableAdapterName>BNKTableAdapter</rd:TableAdapterName>"); //sb.Append("</rd:DataSetInfo>"); sb.Append("</DataSet>"); sb.Append("</DataSets>"); sb.Append("<Body>"); sb.Append("<ReportItems>"); sb.Append("<Tablix Name=\"Tablix1\">"); sb.Append("<TablixBody>"); sb.Append("<TablixColumns>"); for (var i = 0; i < this.dataTable.Columns.Count; i++) { var c = this.dataTable.Columns[i]; sb.Append("<TablixColumn>"); sb.Append("<Width>0.98425in</Width>"); sb.Append("</TablixColumn>"); } sb.Append("</TablixColumns>"); sb.Append("<TablixRows>"); sb.Append("<TablixRow>"); sb.Append("<Height>0.23622in</Height>"); sb.Append("<TablixCells>"); for (var i = 0; i < this.dataTable.Columns.Count; i++) { var c = this.dataTable.Columns[i]; sb.Append("<TablixCell>"); sb.Append("<CellContents>"); sb.Append("<Textbox Name=\"Textbox" + (i + 1).ToString() + "\">"); sb.Append("<CanGrow>true</CanGrow>"); sb.Append("<KeepTogether>true</KeepTogether>"); sb.Append("<Paragraphs>"); sb.Append("<Paragraph>"); sb.Append("<TextRuns>"); sb.Append("<TextRun>"); sb.Append("<Value>" + c.ColumnName + "</Value>"); sb.Append("<Style />"); sb.Append("</TextRun>"); sb.Append("</TextRuns>"); sb.Append("<Style />"); sb.Append("</Paragraph>"); sb.Append("</Paragraphs>"); sb.Append("<rd:DefaultName>Textbox" + (i + 1).ToString() + "</rd:DefaultName>"); sb.Append("<Style>"); sb.Append("<Border>"); sb.Append("<Color>LightGrey</Color>"); sb.Append("<Style>Solid</Style>"); sb.Append("</Border>"); sb.Append("<PaddingLeft>2pt</PaddingLeft>"); sb.Append("<PaddingRight>2pt</PaddingRight>"); sb.Append("<PaddingTop>2pt</PaddingTop>"); sb.Append("<PaddingBottom>2pt</PaddingBottom>"); sb.Append("</Style>"); sb.Append("</Textbox>"); sb.Append("</CellContents>"); sb.Append("</TablixCell>"); } sb.Append("</TablixCells>"); sb.Append("</TablixRow>"); sb.Append("<TablixRow>"); sb.Append("<Height>0.23622in</Height>"); sb.Append("<TablixCells>"); for (var i = 0; i < this.dataTable.Columns.Count; i++) { var c = this.dataTable.Columns[i]; sb.Append("<TablixCell>"); sb.Append("<CellContents>"); sb.Append("<Textbox Name=\"" + c.ColumnName + "\">"); sb.Append("<CanGrow>true</CanGrow>"); sb.Append("<KeepTogether>true</KeepTogether>"); sb.Append("<Paragraphs>"); sb.Append("<Paragraph>"); sb.Append("<TextRuns>"); sb.Append("<TextRun>"); sb.Append("<Value>=Fields!" + c.ColumnName + ".Value</Value>"); sb.Append("<Style />"); sb.Append("</TextRun>"); sb.Append("</TextRuns>"); sb.Append("<Style />"); sb.Append("</Paragraph>"); sb.Append("</Paragraphs>"); sb.Append("<rd:DefaultName>" + c.ColumnName + "</rd:DefaultName>"); sb.Append("<Style>"); sb.Append("<Border>"); sb.Append("<Color>LightGrey</Color>"); sb.Append("<Style>Solid</Style>"); sb.Append("</Border>"); sb.Append("<PaddingLeft>2pt</PaddingLeft>"); sb.Append("<PaddingRight>2pt</PaddingRight>"); sb.Append("<PaddingTop>2pt</PaddingTop>"); sb.Append("<PaddingBottom>2pt</PaddingBottom>"); sb.Append("</Style>"); sb.Append("</Textbox>"); sb.Append("</CellContents>"); sb.Append("</TablixCell>"); } sb.Append("</TablixCells>"); sb.Append("</TablixRow>"); sb.Append("</TablixRows>"); sb.Append("</TablixBody>"); sb.Append("<TablixColumnHierarchy>"); sb.Append("<TablixMembers>"); for (var i = 0; i < this.dataTable.Columns.Count; i++) { sb.Append("<TablixMember />"); } sb.Append("</TablixMembers>"); sb.Append("</TablixColumnHierarchy>"); sb.Append("<TablixRowHierarchy>"); sb.Append("<TablixMembers>"); sb.Append("<TablixMember>"); sb.Append("<KeepWithGroup>After</KeepWithGroup>"); sb.Append("</TablixMember>"); sb.Append("<TablixMember>"); sb.Append("<Group Name=\"详细信息\" />"); sb.Append("</TablixMember>"); sb.Append("</TablixMembers>"); sb.Append("</TablixRowHierarchy>"); sb.Append("<DataSetName>DataSet1</DataSetName>"); sb.Append("<Height>1.2cm</Height>"); sb.Append("<Width>7.5cm</Width>"); sb.Append("<Style>"); sb.Append("<Border>"); sb.Append("<Style>None</Style>"); sb.Append("</Border>"); sb.Append("</Style>"); sb.Append("</Tablix>"); sb.Append("</ReportItems>"); sb.Append("<Height>2in</Height>"); sb.Append("<Style />"); sb.Append("</Body>"); sb.Append("<Width>6.5in</Width>"); sb.Append("<Page>"); sb.Append("<PageHeight>29.7cm</PageHeight>"); sb.Append("<PageWidth>21cm</PageWidth>"); sb.Append("<LeftMargin>2cm</LeftMargin>"); sb.Append("<RightMargin>2cm</RightMargin>"); sb.Append("<TopMargin>2cm</TopMargin>"); sb.Append("<BottomMargin>2cm</BottomMargin>"); sb.Append("<ColumnSpacing>0.13cm</ColumnSpacing>"); sb.Append("<Style />"); sb.Append("</Page>"); sb.Append("<rd:ReportID>" + Guid.NewGuid().ToString() + "</rd:ReportID>"); sb.Append("<rd:ReportUnitType>Cm</rd:ReportUnitType>"); sb.Append("</Report>"); return sb.ToString(); } /// <summary> /// 把DataTable生成excel表 /// </summary> /// <param name="excelPath">要保存的路径</param> public void SaveExcel(string excelPath) { var rdlc = this.GenerateRdlc(); Microsoft.Reporting.WinForms.LocalReport report = new Microsoft.Reporting.WinForms.LocalReport(); report.LoadReportDefinition(new StringReader(rdlc)); report.DataSources.Clear(); report.DataSources.Add(new Microsoft.Reporting.WinForms.ReportDataSource("DataSet1", this.dataTable)); var buf = report.Render("Excel"); report.Dispose(); FileStream fs = new FileStream(excelPath, FileMode.Create); fs.Write(buf, 0, buf.Length); fs.Flush(); fs.Dispose(); } /// <summary> /// 把excel生成一个字节数组 /// </summary> /// <returns>excel</returns> public byte[] GenerateExcel() { var rdlc = this.GenerateRdlc(); using (Microsoft.Reporting.WinForms.LocalReport report = new Microsoft.Reporting.WinForms.LocalReport()) { report.LoadReportDefinition(new StringReader(rdlc)); report.DataSources.Clear(); report.DataSources.Add(new Microsoft.Reporting.WinForms.ReportDataSource("DataSet1", this.dataTable)); var buf = report.Render("Excel"); return buf; } } } }