第五天

学习目的：
    

掌握ADO.NET打开SQL SERVER数据库的方法。

今天做个非常普通的例子，做一个用户登录框。主要是通过这个练习认识一下SQL SERVER数据库的连接方法。和昨天的例子方法基本相同，很容易掌握的。
先建立SQL SERVER数据库，库名为AspNetABC，并建立一Member新表，建表SQL如下：

CREATE TABLE [dbo].[Member] (
    [MemberID] [int] IDENTITY (1, 1) NOT NULL ,
    [MemberName] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,
    [Password] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,
    [Gender] [bit] NOT NULL ,
    [Birthday] [datetime] NULL ,
    [Email] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]

ALTER TABLE [dbo].[Member] WITH NOCHECK ADD
    CONSTRAINT [PK_Member] PRIMARY KEY CLUSTERED
    (
        [MemberID]
    ) ON [PRIMARY]

与上一例子差不多，在web.config文件中再增加一行：
<appSettings>
<add key="数据库1" value="ex01.mdb" />
<add key="SqlDatabase1" value="data source=localhost;user id=sa;password=sa;initial catalog=AspNetABC;Connect Timeout=30" />
</appSettings>

在面中添加二个文本框，txtMemberName、txtPassword，并设置txtPassword的TextMode为Password。设置按钮btnLogin。btnLogin的事件代码如下：

        private void btnLogin_Click(object sender, System.EventArgs e)
        {
            // 先检验输入正确性
            if (txtMemberName.Text == String.Empty || txtMemberName.Text.Trim() == "")
            {
                Response.Write("<script language=javascript>alert('帐号不能为空')</script>");
                return;
            }
            if (txtPassword.Text == String.Empty || txtPassword.Text.Trim() == "")
            {
                Response.Write("<script language=javascript>alert('没有输入密码')</script>");
                return;
            }

            string strConnection = ConfigurationSettings.AppSettings["SqlDatabase1"];
            string sqlMember = "SELECT MemberName ,[Password] FROM Member "
                + " WHERE MemberName = '" + txtMemberName.Text.Trim() + "'"
                + " AND [Password] = '" + txtPassword.Text.Trim() + "'";

            // 连接SqlServer数据库
            SqlConnection conn = new SqlConnection(strConnection);
            // 建立SqlCommand
            SqlCommand cmd = conn.CreateCommand();
            cmd.CommandText = sqlMember;
            conn.Open();
            // 建立DataReader
            SqlDataReader dr = cmd.ExecuteReader();

            // 判断DataReader是否为空记录
            if (dr.HasRows)
            {
                Response.Write("<script language=javascript>alert('" + txtMemberName.Text + "欢迎你！')</script>");
            }
            else
            {
                Response.Write("<script language=javascript>alert('找不到该会员，或密码错误。')</script>");
            }

            // 千万不要忘记关闭DataReader
            dr.Close();

            conn.Close();
        }

好了，一个非常简单的登录框做好了。当然在实际程序中还应加入跳转等，这个就留给你做了。