C#读取Excel文件方法一：直接读取（这种直接读取单元格的方法释放很重要）

Excel.Applicationexcel=null;  
Excel.Workbookswbs=null;  
Excel.Workbookwb=null;  
Excel.Worksheetws=null;  
Excel.Rangerange1=null;  
objectNothing=System.Reflection.Missing.Value;  
 
try  
{  
excel=newExcel.Application();  
excel.UserControl=true;  
excel.DisplayAlerts=false;  
 
excel.Application.Workbooks.Open(this.  
FilePath,Nothing,Nothing,Nothing,Nothing,  
Nothing,Nothing,Nothing,Nothing,Nothing,  
Nothing,Nothing,Nothing);  
 
wbs=excel.Workbooks;  
wb=wbs[1];  
ws=(Excel.Worksheet)wb.Worksheets["Sheet2"];  
 
 
introwCount=ws.UsedRange.Rows.Count;  
intcolCount=ws.UsedRange.Columns.Count;  
if(rowCount<=0)  
thrownewInvalidFormatException  
("文件中没有数据记录");  
if(colCount<4)  
thrownewInvalidFormatException  
("字段个数不对");  
 
for(inti=0;i{  
this.rowNo=i+1;  
object[]row=newobject[4];  
for(intj=0;j<4;j++)  
{  
range1=ws.get_Range(ws.Cells[i+2,j+1],  
ws.Cells[i+2,j+1]);  
row[j]=range1.Value;  
 
if(row[0]==null)  
{  
this.isNullRecord++;  
break;  
}  
}  
 
if(this.isNullRecord>0)  
continue;  
 
DataRowdataRow=this.readExcel(row);  
 
if(this.isNullRecord==1)  
continue;  
 
if(this.verifyData(dataRow)==false)  
errFlag++;  
 
this.updateTableCurr(dataRow);  
}  
}  
finally  
{  
if(excel!=null)  
{  
if(wbs!=null)  
{  
if(wb!=null)  
{  
if(ws!=null)  
{  
if(range1!=null)  
{  
System.Runtime.InteropServices.Marshal.  
ReleaseComObject(range1);  
range1=null;  
}  
System.Runtime.InteropServices.Marshal.  
ReleaseComObject(ws);  
ws=null;  
}  
wb.Close(false,Nothing,Nothing);  
System.Runtime.InteropServices.Marshal.  
ReleaseComObject(wb);  
wb=null;  
}  
wbs.Close();  
System.Runtime.InteropServices.Marshal.  
ReleaseComObject(wbs);  
wbs=null;  
}  
excel.Application.Workbooks.Close();  
excel.Quit();  
System.Runtime.InteropServices.Marshal.  
ReleaseComObject(excel);  
excel=null;  
GC.Collect();  
}  
}  

C#读取Excel文件方法二：通过OleDb连接，把excel文件作为数据源来读取（这里是fill进dataset，也可以返回OleDbDataReader来逐行读，数据较快）

注：这种方法容易把混合型的字段作为null值读取进来，解决办法是改造连接字符串

strConn = "Provider=Microsoft.Jet.  
OLEDB.4.0;Data Source=C:\\Erp1912.xls;Extended   
Properties='Excel8.0;HDR=Yes;IMEX=1'";  

通过Imex=1来把混合型作为文本型读取，避免null值,来实现C#读取Excel文件

privateDataSetimportExcelToDataSet  
(stringFilePath)  
{  
stringstrConn;  
strConn="Provider=Microsoft.Jet.  
OLEDB.4.0;"+"DataSource="+FilePath+";  
ExtendedProperties=Excel8.0;";  
OleDbConnectionconn=newOleDbConnection  
(strConn);  
OleDbDataAdaptermyCommand=newOleDbDataAdapter  
("SELECT*FROM[Sheet1$]",strConn);  
DataSetmyDataSet=newDataSet();  
try  
{  
myCommand.Fill(myDataSet);  
}  
catch(Exceptionex)  
{  
thrownewInvalidFormatException  
("该Excel文件的工作表的名字不正确,"+ex.Message);  
}  
returnmyDataSet;  
} 

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