Specific methods
asp.net connection access code
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<%@ Page language= "C #"%> <%@ import namespace= "System.Data"%> <%@ import namespace= "System.Data.OleDb"%> <script runat= "Server" > Insert page code here // void Page_Load () { String db=@ "Database/data.mdb"; String connstr= "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" +server.mappath (db) + ";"; String sqlcmd= "CREATE TABLE Ieb_webs (ID identity primary key,title varchar (255) Default Null)"; OleDbConnection conn=new OleDbConnection (CONNSTR); Conn. Open (); OleDbCommand olecmd=new OleDbCommand (sqlcmd,conn); Olecmd.executenonquery (); Execute SQL command Response.Write ("Data table build!") "); } Conn. Close (); Conn=null; Olecmd=null; } </script> <body> <form method= "POST" runat= "Server" > <!--Insert content here--> </form> </body>
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Failed to connect to access reason analysis
Failed to process AccessDataSource connection
(1) In the Ch02 folder, create a file named Tio-4-connectionfailure-cs.aspx. In Design view, add a AccessDataSource control to the page that points to Northwind, and the control selects all columns from the table.
(2) Add the GridView to display the information in the data source control. Also, add a Label control and name it "message."
(3) Now switch to Source view and make some changes to the markup, as shown in the following highlighting code. If there is a tag part, it is deleted. The code left should look like the following:
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Chapter 2 TIO #4 Connection failure to Access in C #
Chapter 2 TIO #4 Connection failure to Access in C # Datasourceid= "Accessdatasourcel" Autogeneratecolumns= "true" emptydatatext= "No data records were returned"/> Selectcommand= "Select * FROM Products" Datafile= "~/app_data/northwind.mdb" Onselected= "Accessdatasourcel_selected" /> |
(4) Check the page; When viewing products sold by Northwind, there should be no problem.
(5) The code will now be added to handle the connection problem. Go to the top of the page and go to the following script. The first example is written in C #, and the second example is written in VB. into one of them.
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<%@ Page language= "C #"%> |
Database path Issues
Configure the Access database driver and database file name in Web.config.
Please look at the code
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<appSettings> <add key= "Dbdriver" value= "provider=microsoft.jet.oledb.4.0; Data Source = "/> <add key= "dbname" value= "Company.mdb"/> </appSettings>
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Get the Access database link string in the database access layer, such as OleDBHelper.cs.
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/**////<summary> To obtain a database join string from web.config </summary> To get the database name from the configuration file public static readonly String dbname = ConfigurationManager.AppSettings.Get ("dbname"). ToString (); Get database driver from configuration file public static readonly String dbdriver = ConfigurationManager.AppSettings.Get ("Dbdriver"). ToString (); Get the database connection string private static string dbconnectionstring = Dbdriver + HttpContext.Current.Server.MapPath ( HttpContext.Current.Request.ApplicationPath + "/app_data/") + dbname; To establish a database connection object private static OleDbConnection oledbconn = new OleDbConnection (dbconnectionstring); After this setting, the database can be accessed correctly by the above code, regardless of any subdirectories. |
asp.net connection MSSQL Database
. Net connection to the MS SQL database
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String connectionstring= "Workstation id=" +hostname+ ";p acket size=4096;user id=" +username+ ";p assword=" +password+ "; Data source= "+hostname+";p ersist security info=false;initial catalog= "+databasename; SqlConnection Connection = new System.Data.SqlClient.SqlConnection ();
connection.connectionstring=connectionstring; This. Connection.Open (); System.Data.SqlClient.SqlCommand SelectCommand; selectcommand= new System.Data.SqlClient.SqlCommand ();
SelectCommand.CommandText = "SELECT * from" +TABLENAME;
SelectCommand.Connection = this. Connection;
System.Data.SqlClient.SqlDataReader dr= Selectcommand.executereader (); |
or write like that.
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SqlConnection sql = new SqlConnection (@ "server=.sql2005;integrated Security=sspi; Persist Security info=false;initial catalog=test;data source=7085360cb900427 "); Try { SQL. Open (); if (SQL. state = = ConnectionState.Open Label1. Text = "Connection succeeded!" "; } catch (SqlException S) { MessageBox.Show (s.message); } finally { SQL. Close (); SQL. Dispose (); } |