OleDb方式读入txt、dbf、xls

[txt]

string constr=@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+vsFilePath+";Extended Properties='text;HDR=Yes;FMT=Delimited;IMEX=1;'";
        OleDbDataAdapter da=new OleDbDataAdapter ();
        OleDbConnection OConn=new OleDbConnection ();
        OConn.ConnectionString =constr;
        OConn.Open ();
        OleDbCommand OCmm=new OleDbCommand ();
        OCmm.CommandText ="select * from "+filename+"#txt";
        OCmm.Connection=OConn;
        da.SelectCommand =OCmm;
        OCmm.CommandTimeout=0;
       
        try
        {
         da.Fill(ds,filename);       
        }
        catch(Exception ex)
        {
         throw new Exception("Error！"+ex.Message.ToString());
        }
        finally
        {
         OConn.Close();
        }

[dbf]

string constr="Driver={Microsoft Visual FoxPro Driver};SourceType=DBF;SourceDB="+vsFilePath;
       OdbcDataAdapter da=new OdbcDataAdapter ();
       OdbcConnection OConn=new OdbcConnection ();
       OConn.ConnectionString =constr;
       OConn.Open ();
       OdbcCommand OCmm=new OdbcCommand ();
       OCmm.CommandText ="Select "+fCol+" from "+filename;
       OCmm.Connection=OConn;
       da.SelectCommand =OCmm;
       OCmm.CommandTimeout=0;
       try
       {
        da.Fill(ds,filename);       
       }
       catch(Exception ex)
       {
        throw new Exception("Error！"+ex.Message.ToString());
       }
       finally
       {
        OConn.Close();
       }

[xls]

string constr=@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+vsFilePath+newnm+";Extended Properties='Excel 8.0;HDR=Yes;IMEX=1'";
       OleDbDataAdapter da=new OleDbDataAdapter ();
       OleDbConnection OConn=new OleDbConnection ();
       OConn.ConnectionString =constr;
       OConn.Open ();
       OleDbCommand OCmm=new OleDbCommand ();
       OCmm.CommandText ="select * from [sheet1$]";
       OCmm.Connection=OConn;
       da.SelectCommand =OCmm;
       OCmm.CommandTimeout=0;
       try
       {
        da.Fill(ds,filename);       
       }
       catch(Exception ex)
       {
        throw new Exception("Error！"+ex.Message.ToString());
       }
       finally
       {
        OConn.Close();
       }