select 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 ... platform. LINQ to DataSet and LINQ to Entities both allow you to build LINQ queries that interact with data sourced from SQL Server, either directly (LINQ to Entities) or indirectly (LINQ to ... 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...

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

... either at design time using the property sheet, or at runtime using code. Exporting Using the Report Document When you're exporting using the Report document, you will be using the ExportOptions ... btnExport.Click Dim strExt As String Try With Me.rdHowTo10_4.ExportOptions Select Case lstExportType.SelectedItem The PrintOptions object, found on the ReportDocument, is very useful. ... when you're using tools such as the Viewer in a tabbed form, the tab pages can become cluttered. If you want to limit the power of the Viewer or make it more 10.4 Select Whether the...

Ngày tải lên: 20/10/2013, 13:15

... 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 ... one DataTable to another. Three techniques for selecting records to copy are demonstrated in the following example: • Use the Rows property to access rows in the DataRowCollection of the DataTable ... 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 ... productsDataTable // using the Select( ) method Console.WriteLine(" ;Using the Select( ) method to filter and sort DataRow objects"); productDataRows = productsDataTable .Select( "ProductName ... DataViewRowState myDataViewRowState) where • filterExpression specifies the rows to select. • sortExpression specifies how the selected rows are to be ordered. • myDataViewRowState specifies...

Ngày tải lên: 14/12/2013, 13:15

... object containing a SELECT statement and sets the SelectCommand property of a SqlDataAdapter to that SqlCommand: SqlCommand mySelectCommand = mySqlConnection.CreateCommand(); mySelectCommand.CommandText ... SqlDataAdapter(); mySqlDataAdapter.SelectCommand = mySelectCommand; The SELECT statement is then run when you call the mySqlDataAdapter object's Fill() method to retrieve rows from the Products table ... 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....

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 ... int numOfRows = mySqlDataAdapter.Update(myDataTable); mySqlConnection.Close(); Console.WriteLine("numOfRows = " + numOfRows); Console.WriteLine("myRemoveDataRow.RowState...

Ngày tải lên: 14/12/2013, 13:15

... values. // Get the DataTable from the DataView. DataTable dt = dv.Table; // Filter using the DataTable RowState. DataRow[] delRows = dt .Select( null, null, DataViewRowState.Deleted); ... DataViewRowState enumeration values. Table 2-6. DataViewRowState enumeration Value Description Added The Current version of all Added rows. using System; using System.Configuration; using ... 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 ... this places [ 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 ... 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

... odaSelected.Fill(dtSelected) Me.lstSelected.DataSource = dtSelected Me.lstSelected.DisplayMember = "ProductName" Me.lstSelected.ValueMember = "ProductID" Me.lstSelected.ClearSelected() ... Text Unselected Products ListBox Name lstUnSelected SelectionMode MultiSimple Label Text Selected Products ListBox Name lstSelected SelectionMode MultiSimple Command Button Name btnSelect ... "Northwind"))) odaUnSelected.Fill(dtUnSelected) Me.lstUnSelected.DataSource = dtUnSelected Me.lstUnSelected.DisplayMember = "ProductName" Me.lstUnSelected.ValueMember = "ProductID"...

Ngày tải lên: 14/12/2013, 20:16

... now contains a DataTable named Customers, which contains the rows retrieved by the following SELECT statement set earlier in the SelectCommand property of mySqlDataAdapter: SELECT CustomerID, ... 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...

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

... Set the SelectCommand Property of the SqlAdapter Object to the SqlCommand Object The SelectCommand property contains the SELECT statement you want to run. In the following example, the SelectCommand ... mySqlDataAdapter.SelectCommand = mySqlCommand; This enables you to perform the SELECT statement defined in mySqlCommand. Step 10 actually performs the SELECT statement to retrieve rows from the ... Object to Retrieve the Rows From the Table Call the Fill() method of your SqlDataAdapter object to retrieve the rows from the database, storing these rows locally in a DataTable of your DataSet...

Ngày tải lên: 24/12/2013, 01:17

... then creates a DataTable in the DataSet with the specified name and runs the SELECT statement. The DataTable created in your DataSet is then populated with the rows retrieved by the SELECT statement. ... step 10, and stores the returned DataTable in myDataTable: DataTable myDataTable = myDataSet.Tables["Customers"]; Note You can also specify the DataTable you want to get by passing ... display the columns for each row in the DataTable, // using a DataRow object to access each row in the DataTable foreach (DataRow myDataRow in myDataTable .Rows) { Console.WriteLine("CustomerID...

Ngày tải lên: 24/12/2013, 01:17

Ngày tải lên: 24/12/2013, 06:17