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asp.net common Connection Database Instance code _ practical Skills

Source: Internet
Author: User
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<%@ Page language= "C #" autoeventwireup= "true" codefile= "Default.aspx.cs" inherits= "_default"%>


<center>
</center>
<body>
<form id= "Form1" runat= "Server" >
<div>

<font face= "Song Body" >
<p align= "center" >1. Please enter the corresponding database connection string </p>
<p align= "center" >
<asp:textbox id= "Connstrtextbox" runat= "Server" width= "></asp:TextBox>"
</p>
<p align= "center" >2. Please enter the appropriate SQL query command statement </p>
<p align= "center" >
<asp:textbox id= "Sqltexttextbox" runat= "Server" width= "></asp:TextBox>"
</p>
<p align= "Center" >3. Select the type of database you are connecting to </p>
<p align= "center" >
<asp:dropdownlist id= "dbdropdownlist" runat= "Server" width= "204px" >
<asp:listitem selected= "True" >Access</asp:ListItem>
<asp:ListItem>SQLServer</asp:ListItem>
<asp:ListItem>Oracle</asp:ListItem>
<asp:ListItem>DB2</asp:ListItem>
</asp:DropDownList>
</p>
<p align= "center" >

<asp:button id= "Button1" runat= "Server" onclick= "Button1_Click" text= "Universal Database Connection code test"/>

</p>
<p align= "center" >
<asp:label id= "lblmessage" runat= "Server" font-bold= "True" forecolor= "Red" ></asp:Label>
</p>
</form>
</font>
</div>

asp.net page

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Using System;
Using System.Configuration;
Using System.Data;
Using System.Linq;
Using System.Web;
Using System.Web.Security;
Using System.Web.UI;
Using System.Web.UI.HtmlControls;
Using System.Web.UI.WebControls;
Using System.Web.UI.WebControls.WebParts;
Using System.Xml.Linq;

public partial class _default:system.web.ui.page
{
protected void Page_Load (object sender, EventArgs e)
{
Common database Connection code, here to connect an Access database as a test sample
if (! IsPostBack)
{
Connstrtextbox.text = "Provider=Microsoft.Jet.OLEDB.4.0; Data source= "+ Server.MapPath (" User.mdb ");
Sqltexttextbox.text = "Select COUNT (*) from Info Where name= ' Xiao gu '";
Lblmessage.text = "";
}
}
protected void Button1_Click (object sender, EventArgs e)
{

Defining a database connection string
String myconnectionstring = this. Connstrtextbox.text;
Define SQL statements for query operations
String MySQL = this. Sqltexttextbox.text;
Define the type of database you want to connect to is access
String MyType = this. Dbdropdownlist.selectedvalue;
System.Data.IDbConnection myconnection = null;
Create the appropriate Connection object based on the database type
Switch (MyType)
{
The selected database type is "SQL Server", creating the SqlConnection class database connection object
Case "SQL Server":
myconnection = new System.Data.SqlClient.SqlConnection (myconnectionstring);
Break
Case "Oracle":
myconnection = new System.Data.OracleClient.OracleConnection (myconnectionstring);
Break
The selected database type is "Access" and creates a OleDbConnection class database connection object
Case "Access":
myconnection = new System.Data.OleDb.OleDbConnection (myconnectionstring);
Break
Select a database type of "DB2" to create a OleDbConnection class database connection object
Case "DB2":
myconnection = new System.Data.Odbc.OdbcConnection (myconnectionstring);
Break
Default
myconnection = new System.Data.OleDb.OleDbConnection (myconnectionstring);
Break
}
Execute (myconnection, MySQL);
}
public void Execute (System.Data.IDbConnection myconnection, String strquery)
{
To generate a Command object using the CreateCommand () method
System.Data.IDbCommand mycommand = Myconnection.createcommand ();
Execute a defined SQL query statement
myCommand.CommandText = strquery;
Try
{
Open a database connection
Myconnection.open ();
Define the result information for a query
String MyInfo = "Test connection succeeded!" The records that meet the query requirements are: "+ mycommand.executescalar (). ToString () + "Bar!" ";
Output Query Results information
Lblmessage.text = MyInfo;
}
catch (Exception ex)
{
Output Error exception
Response.Write (ex. ToString ());
}
Finally
{
To close a database connection
Myconnection.close ();
}
}
}

The core code for this procedure is

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The selected database type is "SQL Server", creating the SqlConnection class database connection object
Case "SQL Server":
myconnection = new System.Data.SqlClient.SqlConnection (myconnectionstring);
Break
Case "Oracle":
myconnection = new System.Data.OracleClient.OracleConnection (myconnectionstring);
Break
The selected database type is "Access" and creates a OleDbConnection class database connection object
Case "Access":
myconnection = new System.Data.OleDb.OleDbConnection (myconnectionstring);
Break
Select a database type of "DB2" to create a OleDbConnection class database connection object
Case "DB2":
myconnection = new System.Data.Odbc.OdbcConnection (myconnectionstring);
Break
Default
myconnection = new System.Data.OleDb.OleDbConnection (myconnectionstring);
Break


If you want another connection we can also add some connection code OH.

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