get distinct rows datatable using linq

... data into a LINQ query. Dwonloaded from: iDATA.ws Chapter 18 Using LINQ to DataSet 313 Chapter 18 Quick Reference To Do This Include a DataTable instance in a LINQ query Call the DataTable object’s ... sets using the power of LINQ. Understanding the LINQ to DataSet Provider ADO.NET’s DataTable class, as a logical collection of data-laden objects, is the perfect can- didate for inclusion in LINQ ... Chapter 18 Using LINQ to DataSet 309 with data from external sources, you must bring any data you plan to include in a LINQ query into the relevant DataTable instances before...

Ngày tải lên: 03/10/2013, 00:20

... remotely run SQL statement. While other LINQ providers can be mixed—Chapter 18, Using LINQ to DataSet,” combined LINQ to Objects and LINQ to DataSet content LINQ to Entities imposes restric- tions ... demonstrate one way that LINQ to Entities can be used indirectly with other forms of LINQ. Some LINQ features available with other LINQ providers are not supported by LINQ to Entities. Projections, ... Queries with LINQ to Entities As with all LINQ providers, the general structure of LINQ to Entities queries varies only a little from the LINQ to Objects standard. In fact, looking at a LINQ to Entities...

Ngày tải lên: 03/10/2013, 00:20

... be used in your LINQ to SQL queries. Dwonloaded from: iDATA.ws Chapter 20 Using LINQ to SQL After completing this chapter, you will be able to:  Build LINQ queries that use the LINQ to SQL provider  Understand ... iDATA.ws Chapter 20 Using LINQ to SQL 333 Using LINQ to SQL, especially when building models with its visual designer, is straightforward and often much quicker than setting up a LINQ to Entities ... the first LINQ to Entities query included in Chapter 19, Using LINQ to Entities.” Like its Entity Framework complement, LINQ to SQL uses the clauses in the query (in either the standard LINQ form...

Ngày tải lên: 03/10/2013, 00:20

Ngày tải lên: 18/06/2014, 16:20

Ngày tải lên: 18/06/2014, 16:20

Ngày tải lên: 18/06/2014, 16:20

Ngày tải lên: 18/06/2014, 16:20

... 5.1 Copying Rows from One DataTable to Another Problem You have records in a DataTable that you need to copy to another DataTable. Solution Use the ImportRow( ) method of the DataTable to ... 5-1 . Example 5-1. File: CopyRowsBetweenTablesForm.cs // Namespaces, variables, and constants using System; using System.Configuration; using System.Data; using System.Data.SqlClient; ... the DataTable using the row index. • Use the Select( ) method of the DataTable. • Use the RowFilter property of a DataView for the DataTable. The sample code creates a source DataTable containing...

Ngày tải lên: 28/10/2013, 18:15

... productsDataTable // using the Select() method Console.WriteLine(" ;Using the Select() method to filter and sort DataRow objects"); DataRow[] productDataRows = productsDataTable.Select("ProductID ... objects in productsDataTable // using the Select() method Console.WriteLine(" ;Using the Select() method to filter and sort DataRow objects"); productDataRows = productsDataTable.Select("ProductName ... was modified. None Doesn't match any of the rows in the DataTable. OriginalRows The original rows, which include Unchanged and Deleted rows. Unchanged A row that hasn't been changed....

Ngày tải lên: 14/12/2013, 13:15

... DataAdapter. Using Stored Procedures to Add, Modify, and Remove Rows from the Database You can get a DataAdapter object to call stored procedures to add, modify, and remove rows from the database. ... and remove a DataRow to from a DataTable. The C# methods shown in this section follow the same steps as shown in the earlier section, "Modifying Rows in a DataTable ." Note You'll ... not deleted' ) By using SET NOCOUNT ON before the INSERT, only the number of rows affected by the DELETE statement is returned, and the DataAdapter therefore gets the correct value. Transact-SQL...

Ngày tải lên: 14/12/2013, 13:15

... Calling myDataTable.NewRow() myNewDataRow.RowState = Detached Calling myDataTable .Rows. Add() myNewDataRow.RowState = Added Calling mySqlDataAdapter.Update() numOfRows = 1 myNewDataRow.RowState ... the Add() method through the Rows property // to add the new DataRow to the DataTable Console.WriteLine("Calling myDataTable .Rows. Add()"); myDataTable .Rows. Add(myNewDataRow); Console.WriteLine("myNewDataRow.RowState ... Next, myDataTable .Rows. Add() is called to add myNewDataRow to myDataTable. This causes the RowState of myNewDataRow to change to Added, which indicates myNewDataRow has been added to myDataTable....

Ngày tải lên: 14/12/2013, 13:15

... version values. // Get the DataTable from the DataView. DataTable dt = dv.Table; // Filter using the DataTable RowState. DataRow[] delRows = dt.Select(null, null, DataViewRowState.Deleted); ... 2-6. DataViewRowState enumeration Value Description Added The Current version of all Added rows. using System; using System.Configuration; using System.Text; using System.Data; using System.Data.SqlClient; ... Example 2-6. File: AccessDeletedRowsForm.cs // Namespaces, variables, and constants using System; using System.Configuration; using System.Text; using System.Data; using System.Data.SqlClient;...

Ngày tải lên: 14/12/2013, 18:16

... // Namespaces, variables, and constants using System; using System.Configuration; using System.Windows.Forms; using System.Text; using System.Data; using System.Data.SqlClient; private ... [ Team LiB ] Recipe 3.10 Selecting the Top n Rows in a DataTable Problem You want to create a grid that shows the t op five rows in a DataTable, based on the values in one of the columns. ... sort, and filter records in a DataTable or DataView, there is no method in either class to select the top n rows. The procedure to get the user-specified top n rows with the largest Freight...

Ngày tải lên: 14/12/2013, 18:16

... True Using the GetSql* Methods to Read Column Values In addition to using the Get* methods to read column values as standard C# types, if you are using SQL Server, you can also use the GetSql* ... COLUMN TYPE GET* METHOD C# RETURN TYPE ProductID int GetInt32() int ProductName nvarchar GetString() string UnitPrice money GetDecimal() decimal UnitsInStock smallint GetInt16() short ... StronglyTypedColumnValues.cs illustrates how to read column values as C# types using the Get* methods */ using System; using System.Data; using System.Data.SqlClient; class StronglyTypedColumnValues...

Ngày tải lên: 24/12/2013, 01:17

... illustrates how to read column values as Sql* types using the GetSql* methods */ using System; using System.Data; using System.Data.SqlClient; using System.Data.SqlTypes; class StronglyTypedColumnValuesSql ... GetSql* METHODS COLUMN NAME SQL SERVER COLUMN TYPE GETSql* METHOD Sql* Return Type ProductID int GetInt32() SqlInt32 ProductName nvarchar GetSqlString() SqlString UnitPrice money GetSqlMoney() ... their Get* counterparts. This is because the GetSql*methods don't need to convert between SQL Server types and the standard C# types, which the Get* methods have to do. Tip If you are using...

Ngày tải lên: 24/12/2013, 01:17

... using the SetNull() method of a DataRow. You can also check if a DataColumn contains null using the IsNull() method of a DataRow. 3. Use the Add() method through the Rows property of your DataTable ... the DataTable to // create a new DataRow Console.WriteLine("Calling myDataTable.NewRow()"); DataRow myNewDataRow = myDataTable.NewRow(); Console.WriteLine("myNewDataRow.RowState ... Adding a DataRow to a DataTable In this section, you'll learn how to add a DataRow to a DataTable. Before you see this, let's populate a DataSet with the rows from the Customers...

Ngày tải lên: 24/12/2013, 01:17

... myDataRows) int Update(DataSet myDataSet) int Update (DataTable myDataTable) int Update(DataRow[] myDataRows, DataTableMapping myDataTableMapping) int Update(DataSet myDataSet, string dataTableName) ... Console.WriteLine("Calling myDataTable .Rows. Add()"); myDataTable .Rows. Add(myNewDataRow); Console.WriteLine("myNewDataRow.RowState = " + myNewDataRow.RowState); // step 4: ... • After myDataTable.NewRow() is called to create myNewDataRow, its RowState is Detached, which indicates myNewDataRow isn't yet part of myDataTable. • Next, myDataTable .Rows. Add() is...

Ngày tải lên: 24/12/2013, 01:17

... TYPES, AND GET* METHODS SQL SERVER TYPE COMPATIBLE STANDARD C# TYPE GET* METHOD sql_varient object GetValue() text string GetString() timestamp byte[] GetBytes() tinyint byte GetByte() varbinary ... Using the Get* Methods to Read Column Values Before I show you the other Get* methods that read column values, you need to know the ... timestamp byte[] GetBytes() tinyint byte GetByte() varbinary byte[] GetBytes() varchar string GetString() uniqueidentifier Guid GetGuid() Note You can see the SQL Server types and the values...

Ngày tải lên: 24/12/2013, 01:17

... Cataloging-in-Publication Data: Magennis, Troy, 1970- LINQ to objects using C# 4.0 : using and extending LINQ to objects and parallel LINQ (PLINQ) / Troy Magennis. p. cm. Includes bibliographical ... “What is LINQ? ” is that it’s a moving target. LINQ is built using an open and extensible architecture, and new opera- tors and data sources can be added by anyone. One point is clear: LINQ will ... doc.Close(); } Console.WriteLine(writer.ToString()); } LINQ Approach LINQ to Objects and the new XML programming interface included in C# 3.0 (LINQ to XML, but this example uses the generation side of this API ptg LINQ to Objects...

Ngày tải lên: 24/12/2013, 08:16

Ngày tải lên: 16/01/2014, 16:34