ado net c# example

,Firstname=r.firstname,Lastname=r.lastname,Nationality=r.nationality}). ToList ();}}}}If there is no ToList () method in the hidden code, the running program will report the following error:Additional Information:data binding directly to a store query (DbSet, Dbquery, Dbsqlquery, dbrawsqlquery) are not Supporte D. Instead populate a DbSet with data, for example by calling Load on the DbSet, and then bind to local data. For WPF bind to dbset.local. For

true; } Else { return false; } } Public stringNationname (stringcode) {_cmd.commandtext="Select Name from Nation where [email protected]"; _cmd. Parameters.addwithvalue ("@code", code); _conn. Open (); _DR=_cmd. ExecuteReader (); if(_DR. HasRows) {_dr. Read (); return_dr[0]. ToString (); } Else { return "Han"; } _conn. Close ()

I have been writing something for a long time, and I will write another article before I start school. Recently, I have been playing a database, and I have nothing to do for a winter vacation. I wrote a commemorative day reminder and a personal income and expenditure management.Program.New Access to C # ADO. Net has encountered many difficulties. I hope to help y

Original ADO. NET Entity Data Model, in fact, I do not like to use this, mainly in the case of complex queries, writing a lot of linq statements, of course, can also directly execute SQL statements, however, complex SQL statements cannot be executed because of connection problems.But ADO. NET Entity has the advantage o

C # and database connection operation is essential in the development, and Ado.net is one of the key technologies. Common ado.net have five commonly used objects: SqlConnection database Connection object SqlCommand Database command object SqlDataAdapter data adapter SqlDataReader Database Reader, read-only, forward, can't read data backwards DataSet DataSet , equivalent to a database in memory Here are some common methods for these objects: Execut

Ado. net operation data code Summary (C #) I. Use Sqlconnection Connection SQL Server 1 .. Add namespace Using system. Data. sqlclient; 2. Connect to database Sqlconnection myconnection = new sqlconnection ();Myconnection. connectionstring = "User ID = sa; Password = sinofindb; initial catalog = test; Data Source = 127.0.0.1; Connect timeout = 30 ";Myconnection.

C # ADO. net operation dataCodeSummary1. Use sqlconnection to connect to SQL Server 1. Add a namespace Using system. Data. sqlclient; 2. Connect to the database Sqlconnection myconnection = new sqlconnection (); Myconnection. connectionstring = "User ID = sa; Password = sinofindb; initial Catalog = test; Data Source = 127.0.0.1; Connect timeout = 30 "

}). Distinct (). (c = c.year). ToList ();Return (from R in data. RacesSelect New Class1// {Year= R.date.year// }). ToList ();}}}}The CLASS1 code that is used to produce the collection used by the TreeView controlUsing System;Using System.Collections.Generic;Using System.Linq;Using System.Text;Using System.Threading.Tasks;Namespace WpfApplication73{public static Class F1datacontext{public static formula1v2entities Data {get; set;}}public class Cl

First, deleteString constr = "server=.; Database=test;uid=sa;pwd=sa ";SqlConnection myconnection = new SqlConnection (CONSTR);MyConnection. Open ();String sql = "Delete from students where id=5";SqlCommand sc = new SqlCommand (sql,myconnection);Sc. ExecuteNonQuery ();SqlDataAdapter SDA = new SqlDataAdapter ("SELECT * from students", MyConnection);System.Data.DataSet dr = new System.Data.DataSet ();Sda. Fill (DR, "students");Sda. Update (DR, "students");Viewbag.students = Dr. Tables[0];return Vie

(); Return conn; } }}Using system;using system.collections.generic;using system.linq;using system.text;using System.Data.SqlClient;using System.data;namespace dbcomm{Static class Dbtablesource {public static DataTable GetSource (SqlConnection Co NN, string strsql) {DataTable dt = null; SqlCommand cmd = null; SqlDataAdapter ad = null; try {lock (dt = new DataTable ()) {if (conn is SqlConnection) {cmd = new SqlC

Tags: Using system;using system.collections.generic;using system.linq;using system.text;using System.Windows;using System.windows.controls;using system.windows.data;using system.windows.documents;using System.Windows.Input;using System.windows.media;using system.windows.media.imaging;using system.windows.navigation;using System.windows.shapes;using system.data.sqlclient;using system.data;namespace Wpf{//C # ADO