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<center>
<h2><font face="宋体">访问数据库的通用代码实例</font>
</h2>
</center>
<body>
<form id="form1" runat="server">
<div>
<font face="宋体">
<p align="center">1.请输入相应数据库连接字符串</p>
<p align="center">
<asp:TextBox id="ConnStrTextBox" runat="server" Width="600"></asp:TextBox>
</p>
<p align="center">2.请输入相应SQL查询命令语句</p>
<p align="center">
<asp:TextBox id="SqlTextTextBox" runat="server" Width="600"></asp:TextBox>
</p>
<p align="center">3.请选择所连接的数据库类型</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="通用数据库连接代码测试" />
</p>
<p align="center">
<asp:Label id="lblMessage" runat="server" Font-Bold="True" ForeColor="Red"></asp:Label>
</p>
</form>
</font>
</div>
asp.net页面
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//通用数据库连接代码，这里以连接Access数据库为测试示例
if (!IsPostBack)
{
ConnStrTextBox.Text = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" + Server.MapPath("User.mdb");
SqlTextTextBox.Text = "Select COUNT(*) From Info Where Name='小顾'";
lblMessage.Text = "";
}
}
protected void Button1_Click(object sender, EventArgs e)
{
//定义数据库连接字符串
string MyConnectionString = this.ConnStrTextBox.Text;
//定义查询操作的SQL语句
string MySQL = this.SqlTextTextBox.Text;
//定义所要连接的数据库类型为Access
string MyType = this.DBDropDownList.SelectedValue;
System.Data.IDbConnection MyConnection = null;
// 根据数据库类型，创建相应的 Connection 对象
switch (MyType)
{
//选择的数据库类型为“SQLServer”，创建SqlConnection类数据库连接对象
case "SQLServer":
MyConnection = new System.Data.SqlClient.SqlConnection(MyConnectionString);
break;
case "Oracle":
MyConnection = new System.Data.OracleClient.OracleConnection(MyConnectionString);
break;
//选择的数据库类型为“Access”，创建OleDbConnection类数据库连接对象
case "Access":
MyConnection = new System.Data.OleDb.OleDbConnection(MyConnectionString);
break;
//选择的数据库类型为“DB2”，创建OleDbConnection类数据库连接对象
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)
{
//使用 CreateCommand() 方法生成 Command 对象
System.Data.IDbCommand MyCommand = MyConnection.CreateCommand();
//执行定义的SQL查询语句
MyCommand.CommandText = strquery;
try
{
//打开数据库连接
MyConnection.Open();
//定义查询的结果信息
String MyInfo = "测试连接成功！符合查询要求的记录共有：" + MyCommand.ExecuteScalar().ToString() + "条！";
//输出查询结果信息
lblMessage.Text = MyInfo;
}
catch (Exception ex)
{
//输出错误异常
Response.Write(ex.ToString());
}
finally
{
//关闭数据库连接
MyConnection.Close();
}
}
}
本段程序的核心代码为
