joinステートメントを使用して2つの異なるデータセットからC＃で1つにデータをリンクする

Question

1つのデータテーブル（facilData）と別のデータテーブル（ownerData）のデータを取得し、別のデータテーブル（dataStore）に書き込もうとしています。 2番目は最初のものと同じではありません。以下のコードを試してみましたが、次のエラーが表示されます。"System.StringとSystem.Stringの型が一致しません"。次に、デバッガが私を取り戻し、下のコードで（int）table2 ["rowIndex"]をハイライト表示します。

public void Write2Sheet(DataTable dt1, DataTable dt2, DataTable dt3, String newFilePath) 
    { 
     try 
     { 
      //Merge the three Datatables into the single Datatable source 
      var mdata = from table1 in facilData.AsEnumerable() 
         join table2 in ownerData.AsEnumerable() on (int)table1["rowIndex"] equals (int)table2["rowIndex"] 
         select new 
         { 
          rowIndex = (int)table1["rowIndex"], 
          Prog = (string)table1["Prog"], 
          cStatus = (string)table1["cStatus"], 
          bStatus = (string)table1["bStatus"], 
          fID = (string)table1["fID"], 
          fNam = (string)table1["fNam"], 
          fAdd = (string)table1["fAdd"], 
          fCity = (string)table1["fCity"], 
          fState = (string)table1["fState"], 
          fCode = (string)table1["fCode"], 
          oInfo = (string)table2["oInfo"], 
          pgRecId = (string)table1["pgRecId"], 
          lAct = (string)table1["lAct"] 
         }; 

      foreach (var rec in mdata) 
      { 
       var row = dataStore.NewRow(); 
       row["rowIndex"] = rec.rowIndex; 
       row["Prog"] = rec.Prog; 
       row["cStatus"] = rec.cStatus; 
       row["bStatus"] = rec.bStatus; 
       row["fID"] = rec.fID; 
       row["fNam"] = rec.fNam; 
       row["fAdd"] = rec.fAdd; 
       row["fCity"] = rec.fCity; 
       row["fState"] = rec.fState; 
       row["fCode"] = rec.fCode; 
       row["oInfo"] = rec.oInfo; 
       row["pgRecId"] = rec.pgRecId; 
       row["lAct"] = rec.lAct; 


       dataStore.Rows.Add(row); 
      } 
     } 
     catch (Exception e) 
     { 
      Write2LogFile("The data tables couldn't merge because: " + e.Message); 
     } 

     //Write from the Datatable source to the new spreadsheet and save it 
     try 
     { 
      FileInfo newSheet = new FileInfo(fileName); 
      using (ExcelPackage xPkg = new ExcelPackage(newSheet)) 
      { 
       ExcelWorksheet worksheet = xPkg.Workbook.Worksheets[1]; 
       var cell = worksheet.Cells; 
       int rI = 2; 

       foreach (DataRow dr in dataStore.Rows) 
       { 
        string iDX = rI.ToString(); 

        worksheet.Cells["A" + iDX].Value = dr["Prog"].ToString(); 
        worksheet.Cells["B" + iDX].Value = dr["cStatus"].ToString(); 
        worksheet.Cells["C" + iDX].Value = dr["bStatus"].ToString(); 
        worksheet.Cells["D" + iDX].Value = dr["fID"].ToString(); 
        worksheet.Cells["E" + iDX].Value = dr["fNam"].ToString(); 
        worksheet.Cells["F" + iDX].Value = dr["fAdd"].ToString(); 
        worksheet.Cells["G" + iDX].Value = dr["fCity"].ToString(); 
        worksheet.Cells["H" + iDX].Value = dr["fState"].ToString(); 
        worksheet.Cells["I" + iDX].Value = dr["fCode"].ToString(); 
        worksheet.Cells["J" + iDX].Value = dr["oInfo"].ToString(); 
        worksheet.Cells["K" + iDX].Value = dr["pgRecId"].ToString(); 
        worksheet.Cells["L" + iDX].Value = dr["lAct"].ToString(); 

        rI++; 
       } 

       xPkg.Save(); 
      } 
     } 
     catch (Exception ex) 
     { 
      Write2LogFile("Data was not written to spreadsheet because: " + ex.Message); 
     } 
    } 

Answer 1

私はそれを理解しました。クエリ構文を実行しようとするのではなく、メソッド構文を使用しました。私は単一のデータテーブルに追加したいオブジェクトのコンテナとして追加のクラスを追加しました。 row-indexのどれもがnullではありませんが、とにかくnullチェックを追加しました。

public void Write2Sheet(DataTable dt1, DataTable dt2, DataTable dt3, String newFilePath) 
    { 
     try 
     { 
      //Merge the three Datatables into the single Datatable source 

      //method syntax 
      var mdata = facilData.AsEnumerable().Where(f => f[0] != typeof(DBNull)).Join(ownerData.AsEnumerable(), 
         table1 => table1.Field<int>(0), 
         table2 => table2.Field<int>(0), 
         (table1, table2) => new Class1 //container class 
         { 
          rowIndex = (int)table1[0], 
          Prog = table1[1].ToString(), 
          cStatus = table1[2].ToString(), 
          bStatus = table1[3].ToString(), 
          fID = table1[4].ToString(), 
          fNam = table1[5].ToString(), 
          fAdd = table1[6].ToString(), 
          fCity = table1[7].ToString(), 
          fState = table1[8].ToString(), 
          fCode = table1[9].ToString(), 
          oInfo = table2[1].ToString(), 
          pgRecId = table1[10].ToString(), 
          lAct = table1[11].ToString() 
         }); 

      foreach (var rec in mdata) 
      { 
       var row = dataStore.NewRow(); 
       row["rowIndex"] = rec.rowIndex; 
       row["Prog"] = rec.Prog; 
       row["cStatus"] = rec.cStatus; 
       row["bStatus"] = rec.bStatus; 
       row["fID"] = rec.fID; 
       row["fNam"] = rec.fNam; 
       row["fAdd"] = rec.fAdd; 
       row["fCity"] = rec.fCity; 
       row["fState"] = rec.fState; 
       row["fCode"] = rec.fCode; 
       row["oInfo"] = rec.oInfo; 
       row["pgRecId"] = rec.pgRecId; 
       row["lAct"] = rec.lAct; 


       dataStore.Rows.Add(row); 
      } 
     } 
     catch (Exception e) 
     { 
      Write2LogFile("The data tables couldn't merge because: " + e.Message); 
     } 

     //Write from the Datatable source to the new spreadsheet and save it 
     try 
     { 
      FileInfo newSheet = new FileInfo(fileName); 
      using (ExcelPackage xPkg = new ExcelPackage(newSheet)) 
      { 
       ExcelWorksheet worksheet = xPkg.Workbook.Worksheets[1]; 
       var cell = worksheet.Cells; 
       int rI = 2; 

       foreach (DataRow dr in dataStore.Rows) 
       { 
        string iDX = rI.ToString(); 

        worksheet.Cells["A" + iDX].Value = dr["Prog"].ToString(); 
        worksheet.Cells["B" + iDX].Value = dr["cStatus"].ToString(); 
        worksheet.Cells["C" + iDX].Value = dr["bStatus"].ToString(); 
        worksheet.Cells["D" + iDX].Value = dr["fID"].ToString(); 
        worksheet.Cells["E" + iDX].Value = dr["fNam"].ToString(); 
        worksheet.Cells["F" + iDX].Value = dr["fAdd"].ToString(); 
        worksheet.Cells["G" + iDX].Value = dr["fCity"].ToString(); 
        worksheet.Cells["H" + iDX].Value = dr["fState"].ToString(); 
        worksheet.Cells["I" + iDX].Value = dr["fCode"].ToString(); 
        worksheet.Cells["J" + iDX].Value = dr["oInfo"].ToString(); 
        worksheet.Cells["K" + iDX].Value = dr["pgRecId"].ToString(); 
        worksheet.Cells["L" + iDX].Value = dr["lAct"].ToString(); 

        rI++; 
       } 

       xPkg.Save(); 
       MessageBox.Show("Data was successfully added to the current spreadsheet."); 
      } 
     } 
     catch (Exception ex) 
     { 
      Write2LogFile("Data was not written to spreadsheet because: " + ex.Message); 
     } 
    }