Linq on DataTable select specific column into datatable not whole table

Question

I m running a LINQ query on a datatable in c    I want to select specific columns rather than the whole row and enter the result into a datatable  How can i do that    My Code   public DataTable getConversions string c to  string p to        var query   from r in matrix AsEnumerable                   where r Field lt string gt   c to      c to  amp  amp                        r Field lt string gt   p to      p to                 select r       DataTable conversions   query CopyToDataTable

User · Answer

Your select statement is returning a sequence of anonymous type , not a sequence of DataRows. CopyToDataTable() is only available on IEnumerable<T> where T is or derives from DataRow. You can select r the row object to call CopyToDataTable on it.

var query = from r in matrix.AsEnumerable()
                where r.Field<string>("c_to") == c_to &&
                      r.Field<string>("p_to") == p_to
                 select r;

DataTable conversions = query.CopyToDataTable();

You can also implement CopyToDataTable Where the Generic Type T Is Not a DataRow.

User · Answer

LINQ is very effective and easy to use on Lists rather than DataTable  I can see the above answers have a loop for  foreach   which I will not prefer    So the best thing to select a perticular column from a DataTable is just use a DataView to filter the column and use it as you want    Find it here how to do this   DataView dtView   new DataView dtYourDataTable   DataTable dtTableWithOneColumn  dtView  ToTable true   ColumnA      Now the DataTable dtTableWithOneColumn contains only one column ColumnA

User · Answer

Try Access DataTable easiest way which can help you for getting perfect idea for accessing DataTable  DataSet using Linq     Consider following example  suppose we have DataTable like below   DataTable ObjDt   new DataTable  List    ObjDt Columns Add  WorkName   typeof string    ObjDt Columns Add  Price   typeof decimal    ObjDt Columns Add  Area   typeof string    ObjDt Columns Add  Quantity  typeof int    ObjDt Columns Add  Breath  typeof decimal    ObjDt Columns Add  Length  typeof decimal      Here above is the code for DatTable  here we assume that there are some data are available in this DataTable  and we have to bind Grid view of particular by processing some data as shown below      Area   Quantity   Breath   Length   Price   Quantity   breath  Length   Than we have to fire following query which will give us exact result as we want   var data   ObjDt AsEnumerable   Select              r   gt  new                               Area   r Field lt string gt   Area                    Que   r Field lt int gt   Quantity                    Breath   r Field lt decimal gt   Breath                    Length   r Field lt decimal gt   Length                    totLen   r Field lt int gt   Quantity      r Field lt decimal gt   Breath     r Field lt decimal gt   Length                   ToList      We just have to assign this data variable as Data Source   By using this simple Linq query we can get all our accepts  and also we can perform all other LINQ queries with this

User · Answer

Here I get only three specific columns from mainDataTable and use the filter  DataTable checkedParams   mainDataTable Select  checked   true   CopyToDataTable    DefaultView ToTable false   lagerID    reservePeriod    discount

User · Answer

If you already know beforehand how many columns your new DataTable would have  you can do something like this   DataTable matrix          get matrix values from db  DataTable newDataTable   new DataTable    newDataTable Columns Add  c to   typeof string    newDataTable Columns Add  p to   typeof string     var query   from r in matrix AsEnumerable               where r Field lt string gt   c to       foo   amp  amp                      r Field lt string gt   p to       bar              let objectArray   new object                                 r Field lt string gt   c to    r Field lt string gt   p to                             select objectArray   foreach  var array in query        newDataTable Rows Add array

[c#] Linq on DataTable: select specific column into datatable, not whole table

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