Csharp/C#教程：C#读取csv格式文件的方法分享

本文实例讲述了C#读取csv格式文件的方法。分享给大家供大家参考。具体实现方法如下：

一、CSV文件规则
 
1开头是不留空，以行为单位。
2可含或不含列名，含列名则居文件第一行。
3一行数据不跨行，无空行。
4以半角逗号（即,）作分隔符，列为空也要表达其存在。
5列内容如存在半角逗号（即,）则用半角引号（即’,’）将该字段值包含起来。
6列内容如存在半角引号（即”）则应替换成半角双引号（””）转义，并用半角引号（即””）将该字段值包含起来。
7文件读写时引号，逗号操作规则互逆。
8内码格式不限，可为ASCII、Unicode或者其他。
9不支持特殊字符
 
二、C#读取csv文件的方法

代码如下://读CSV文件类,读取指定的CSV文件，可以导出DataTable
   publicclassCsvStreamReader
   {
       privateArrayListrowAL;        //行链表,CSV文件的每一行就是一个链
       privatestringfileName;       //文件名
       privateEncodingencoding;       //编码
       publicCsvStreamReader()
       {
           this.rowAL=newArrayList();
           this.fileName=””;
           this.encoding=Encoding.Default;
       }
       ///<summary>
       ///
       ///</summary>
       ///<paramname=”fileName”>文件名,包括文件路径</param>
       publicCsvStreamReader(stringfileName)
       {
           this.rowAL=newArrayList();
           this.fileName=fileName;
           this.encoding=Encoding.Default;
           LoadCsvFile();
       }
       ///<summary>
       ///
       ///</summary>
       ///<paramname=”fileName”>文件名,包括文件路径</param>
       ///<paramname=”encoding”>文件编码</param>
       publicCsvStreamReader(stringfileName,Encodingencoding)
       {
           this.rowAL=newArrayList();
           this.fileName=fileName;
           this.encoding=encoding;
           LoadCsvFile();
       }
       ///<summary>
       ///文件名,包括文件路径
       ///</summary>
       publicstringFileName
       {
           set
           {
               this.fileName=value;
               LoadCsvFile();
           }
       }
       ///<summary>
       ///文件编码
       ///</summary>
       publicEncodingFileEncoding
       {
           set
           {
               this.encoding=value;
           }
       }
       ///<summary>
       ///获取行数
       ///</summary>
       publicintRowCount
       {
           get
           {
               returnthis.rowAL.Count;
           }
       }
       ///<summary>
       ///获取列数
       ///</summary>
       publicintColCount
       {
           get
           {
               intmaxCol;
               maxCol=0;
               for(inti=0;i<this.rowAL.Count;i++)
               {
                   ArrayListcolAL=(ArrayList)this.rowAL[i];
                   maxCol=(maxCol>colAL.Count)?maxCol:colAL.Count;
               }
               returnmaxCol;
           }
       }

       ///<summary>
       ///获取某行某列的数据
       ///row:行,row=1代表第一行
       ///col:列,col=1代表第一列 
       ///</summary>
       publicstringthis[introw,intcol]
       {
           get
           {
               //数据有效性验证
               CheckRowValid(row);
               CheckColValid(col);
               ArrayListcolAL=(ArrayList)this.rowAL[row-1];
               //如果请求列数据大于当前行的列时,返回空值
               if(colAL.Count<col)
               {
                   return””;
               }
               returncolAL[col-1].ToString();
           }
       }

       ///<summary>
       ///根据最小行，最大行，最小列，最大列，来生成一个DataTable类型的数据
       ///行等于1代表第一行
       ///列等于1代表第一列
       ///maxrow:-1代表最大行
       ///maxcol:-1代表最大列
       ///</summary>
       publicDataTablethis[intminRow,intmaxRow,intminCol,intmaxCol]
       {
           get
           {
               //数据有效性验证
               CheckRowValid(minRow);
               CheckMaxRowValid(maxRow);
               CheckColValid(minCol);
               CheckMaxColValid(maxCol);
               if(maxRow==-1)
               {
                   maxRow=RowCount;
               }
               if(maxCol==-1)
               {
                   maxCol=ColCount;
               }
               if(maxRow<minRow)
               {
                   thrownewException(“最大行数不能小于最小行数”);
               }
               if(maxCol<minCol)
               {
                   thrownewException(“最大列数不能小于最小列数”);
               }
               DataTablecsvDT=newDataTable();
               inti;
               intcol;
               introw;
               //增加列
               for(i=minCol;i<=maxCol;i++)
               {
                   csvDT.Columns.Add(i.ToString());
               }
               for(row=minRow;row<=maxRow;row++)
               {
                   DataRowcsvDR=csvDT.NewRow();
                   i=0;
                   for(col=minCol;col<=maxCol;col++)
                   {
                       csvDR[i]=this[row,col];
                       i++;
                   }
                   csvDT.Rows.Add(csvDR);
               }
               returncsvDT;
           }
       }

       ///<summary>
       ///检查行数是否是有效的
       ///</summary>
       ///<paramname=”col”></param> 
       privatevoidCheckRowValid(introw)
       {
           if(row<=0)
           {
               thrownewException(“行数不能小于0”);
           }
           if(row>RowCount)
           {
               thrownewException(“没有当前行的数据”);
           }
       }
       ///<summary>
       ///检查最大行数是否是有效的
       ///</summary>
       ///<paramname=”col”></param> 
       privatevoidCheckMaxRowValid(intmaxRow)
       {
           if(maxRow<=0&&maxRow!=-1)
           {
               thrownewException(“行数不能等于0或小于-1”);
           }
           if(maxRow>RowCount)
           {
               thrownewException(“没有当前行的数据”);
           }
       }
       ///<summary>
       ///检查列数是否是有效的
       ///</summary>
       ///<paramname=”col”></param> 
       privatevoidCheckColValid(intcol)
       {
           if(col<=0)
           {
               thrownewException(“列数不能小于0”);
           }
           if(col>ColCount)
           {
               thrownewException(“没有当前列的数据”);
           }
       }
       ///<summary>
       ///检查检查最大列数是否是有效的
       ///</summary>
       ///<paramname=”col”></param> 
       privatevoidCheckMaxColValid(intmaxCol)
       {
           if(maxCol<=0&&maxCol!=-1)
           {
               thrownewException(“列数不能等于0或小于-1”);
           }
           if(maxCol>ColCount)
           {
               thrownewException(“没有当前列的数据”);
           }
       }
       ///<summary>
       ///载入CSV文件
       ///</summary>
       privatevoidLoadCsvFile()
       {
           //对数据的有效性进行验证
           if(this.fileName==null)
           {
               thrownewException(“请指定要载入的CSV文件名”);
           }
           elseif(!File.Exists(this.fileName))
           {
               thrownewException(“指定的CSV文件不存在”);
           }
           else
           {
           }
           if(this.encoding==null)
           {
               this.encoding=Encoding.Default;
           }
           StreamReadersr=newStreamReader(this.fileName,this.encoding);
           stringcsvDataLine;
           csvDataLine=””;
           while(true)
           {
               stringfileDataLine;
               fileDataLine=sr.ReadLine();
               if(fileDataLine==null)
               {
                   break;
               }
               if(csvDataLine==””)
               {
                   csvDataLine=fileDataLine;//GetDeleteQuotaDataLine(fileDataLine);
               }
               else
               {
                   csvDataLine+=”\r\n”+fileDataLine;//GetDeleteQuotaDataLine(fileDataLine);
               }
               //如果包含偶数个引号，说明该行数据中出现回车符或包含逗号
               if(!IfOddQuota(csvDataLine))
               {
                   AddNewDataLine(csvDataLine);
                   csvDataLine=””;
               }
           }
           sr.Close();
           //数据行出现奇数个引号
           if(csvDataLine.Length>0)
           {
               thrownewException(“CSV文件的格式有错误”);
           }
       }
       ///<summary>
       ///获取两个连续引号变成单个引号的数据行
       ///</summary>
       ///<paramname=”fileDataLine”>文件数据行</param>
       ///<returns></returns>
       privatestringGetDeleteQuotaDataLine(stringfileDataLine)
       {
           returnfileDataLine.Replace(“\”\””,”\””);
       }
       ///<summary>
       ///判断字符串是否包含奇数个引号
       ///</summary>
       ///<paramname=”dataLine”>数据行</param>
       ///<returns>为奇数时，返回为真；否则返回为假</returns>
       privateboolIfOddQuota(stringdataLine)
       {
           intquotaCount;
           booloddQuota;
           quotaCount=0;
           for(inti=0;i<dataLine.Length;i++)
           {
               if(dataLine[i]==’\”‘)
               {
                   quotaCount++;
               }
           }
           oddQuota=false;
           if(quotaCount%2==1)
           {
               oddQuota=true;
           }
           returnoddQuota;
       }
       ///<summary>
       ///判断是否以奇数个引号开始
       ///</summary>
       ///<paramname=”dataCell”></param>
       ///<returns></returns>
       privateboolIfOddStartQuota(stringdataCell)
       {
           intquotaCount;
           booloddQuota;
           quotaCount=0;
           for(inti=0;i<dataCell.Length;i++)
           {
               if(dataCell[i]==’\”‘)
               {
                   quotaCount++;
               }
               else
               {
                   break;
               }
           }
           oddQuota=false;
           if(quotaCount%2==1)
           {
               oddQuota=true;
           }
           returnoddQuota;
       }
       ///<summary>
       ///判断是否以奇数个引号结尾
       ///</summary>
       ///<paramname=”dataCell”></param>
       ///<returns></returns>
       privateboolIfOddEndQuota(stringdataCell)
       {
           intquotaCount;
           booloddQuota;
           quotaCount=0;
           for(inti=dataCell.Length-1;i>=0;i–)
           {
               if(dataCell[i]==’\”‘)
               {
                   quotaCount++;
               }
               else
               {
                   break;
               }
           }
           oddQuota=false;
           if(quotaCount%2==1)
           {
               oddQuota=true;
           }
           returnoddQuota;
       }
       ///<summary>
       ///加入新的数据行
       ///</summary>
       ///<paramname=”newDataLine”>新的数据行</param>
       privatevoidAddNewDataLine(stringnewDataLine)
       {
           //System.Diagnostics.Debug.WriteLine(“NewLine:”+newDataLine);
           ////return;
           ArrayListcolAL=newArrayList();
           string[]dataArray=newDataLine.Split(‘,’);
           booloddStartQuota;       //是否以奇数个引号开始
           stringcellData;
           oddStartQuota=false;
           cellData=””;
           for(inti=0;i<dataArray.Length;i++)
           {
               if(oddStartQuota)
               {
                   //因为前面用逗号分割,所以要加上逗号
                   cellData+=”,”+dataArray[i];
                   //是否以奇数个引号结尾
                   if(IfOddEndQuota(dataArray[i]))
                   {
                       colAL.Add(GetHandleData(cellData));
                       oddStartQuota=false;
                       continue;
                   }
               }
               else
               {
                   //是否以奇数个引号开始
                   if(IfOddStartQuota(dataArray[i]))
                   {
                       //是否以奇数个引号结尾,不能是一个双引号,并且不是奇数个引号
                       if(IfOddEndQuota(dataArray[i])&&dataArray[i].Length>2&&!IfOddQuota(dataArray[i]))
                       {
                           colAL.Add(GetHandleData(dataArray[i]));
                           oddStartQuota=false;
                           continue;
                       }
                       else
                       {
                           oddStartQuota=true;
                           cellData=dataArray[i];
                           continue;
                       }
                   }
                   else
                   {
                       colAL.Add(GetHandleData(dataArray[i]));
                   }
               }
           }
           if(oddStartQuota)
           {
               thrownewException(“数据格式有问题”);
           }
           this.rowAL.Add(colAL);
       }

       ///<summary>
       ///去掉格子的首尾引号，把双引号变成单引号
       ///</summary>
       ///<paramname=”fileCellData”></param>
       ///<returns></returns>
       privatestringGetHandleData(stringfileCellData)
       {
           if(fileCellData==””)
           {
               return””;
           }
           if(IfOddStartQuota(fileCellData))
           {
               if(IfOddEndQuota(fileCellData))
               {
                   returnfileCellData.Substring(1,fileCellData.Length-2).Replace(“\”\””,”\””);//去掉首尾引号，然后把双引号变成单引号
               }
               else
               {
                   thrownewException(“数据引号无法匹配”+fileCellData);
               }
           }
           else
           {
               //考虑形如””   “”””     “”””””  
               if(fileCellData.Length>2&&fileCellData[0]==’\”‘)
               {
                   fileCellData=fileCellData.Substring(1,fileCellData.Length-2).Replace(“\”\””,”\””);//去掉首尾引号，然后把双引号变成单引号
               }
           }
           returnfileCellData;
       }
   }

希望本文所述对大家的C#程序设计有所帮助。

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