Wie verwendet man "Gruppieren nach" LINQ?

Question

Ich benutze Linq mit DataSet für Excel-Multi-Blatt. Wie verwendet man die Gruppierung nach LINQ?

Beispieldaten:

Name  | Rate | Date  | Code | ROW_SEQ 
A   | 12 | 01/01/2015 | 12 | 1 
B   | 13 | 01/01/2015 | 12 | 2 
Sub Total | 25 | 01/01/2015 | 12 | 
C   | 10 | 01/01/2015 | 12 | 3 
Grand Total | 35 | 01/01/2015 | 12 | 
D   | 15 | 10/01/2015 | 15 | 1 
E   | 16 | 10/01/2015 | 15 | 2 
Sub Total | 31 | 10/01/2015 | 15 | 
F   | 10 | 10/01/2015 | 15 | 3 
Grand Total | 41 | 10/01/2015 | 15 | 

C# Code:

protected void btnExportExcel_Click(object sender, EventArgs e) 
{    
    /*== How to use Group by LINQ? ==*/ 
    DataSet dsTmp = new DataSet(); 
    DataTable dtTmp = dtExport.Copy(); 
    var grouped = from table in dtTmp.AsEnumerable() 
     group table by new { date_Col = table["date"] , code_Col = table["code"] } into groupby 
     select new 
     { 
      Value = groupby.Key, 
      ColumnValues = groupby 
     }; 
    /*== How to use Group by LINQ? ==*/ 

    foreach (var key in grouped) 
    { 
     dtTmp = new DataTable(); 
     dtTmp = dtExport.Clone(); 
     dtTmp.TableName = (key.Value.settle_date_Col + "-" + key.Value.bank_code_Col).Replace("00:00:00", "").Replace("/",""); 
     foreach (var rw in key.ColumnValues) 
     { 
      dtTmp.ImportRow(rw); 
     } 
     dtTmp.AcceptChanges(); 
     dsTmp.Tables.Add(dtTmp.Copy()); 
    } 
    dsTmp.AcceptChanges(); 
    string fileName = string.Format("{0}_{1}.xls", this._ID, DateTime.Now.ToString("yyyyMMdd_HHmmss")); 
    ExcelMultiSheet.ToExcel(dsTmp, fileName, Page.Response);   

} 

-Code Ergebnisse:

Sheet1 
Name  | Rate | Date  | Code | ROW_SEQ 
A   | 12 | 01/01/2015 | 12 | 1 
B   | 13 | 01/01/2015 | 12 | 2 
C   | 10 | 01/01/2015 | 12 | 3 

Sheet2 
Name  | Rate | Date  | Code | ROW_SEQ 
Sub Total | 25 | 01/01/2015 | 12 | 
Grand Total | 35 | 01/01/2015 | 12 | 

Sheet3 
Name  | Rate | Date  | Code | ROW_SEQ 
D   | 15 | 10/01/2015 | 15 | 1 
E   | 16 | 10/01/2015 | 15 | 2 
F   | 10 | 10/01/2015 | 15 | 3 

Sheet4 
Name  | Rate | Date  | Code | ROW_SEQ 
Sub Total | 31 | 10/01/2015 | 15 | 
Grand Total | 41 | 10/01/2015 | 15 | 

Aber ich brauche Ergebnisse:

Sheet1 
    Name  | Rate | Date  | Code | ROW_SEQ 
    A   | 12 | 01/01/2015 | 12 | 1 
    B   | 13 | 01/01/2015 | 12 | 2 
    Sub Total | 25 | 01/01/2015 | 12 | 
    C   | 10 | 01/01/2015 | 12 | 3 
    Grand Total | 35 | 01/01/2015 | 12 | 

Sheet2 
    Name  | Rate | Date  | Code | ROW_SEQ 
    D   | 15 | 10/01/2015 | 15 | 1 
    E   | 16 | 10/01/2015 | 15 | 2 
    Sub Total | 31 | 10/01/2015 | 15 | 
    F   | 10 | 10/01/2015 | 15 | 3 
    Grand Total | 41 | 10/01/2015 | 15 | 

Dank voraus. :)

Answer 1

können Sie mögen verwenden diese

var results = from p in persons 
       group p.car by p.PersonId into g 
       select new { PersonID = g.Key, Cars = g.ToList() };