C#连接数据库代码(基础)_c#链接数据库代码-优快云博客

本文链接：https://blog.youkuaiyun.com/wangliuran/article/details/50809499

本文提供了一个使用C#进行SQL数据库操作的示例，包括连接数据库、插入、删除、更新和查询数据等基本功能。通过这个示例，读者可以了解到如何在C#应用程序中实现对SQL Server数据库的基本CRUD操作。

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<pre name="code" class="csharp">    //string connStr = "server=xx.xx.xx.xx;database=xxDB;uid=sa;password=xxx";
    private static string connStr = System.Configuration.ConfigurationSettings.AppSettings["Connection"].ToString();//web.config  <appSettings><add key="Connection" value="server=xx.xx.xx.xx;database=xxDB;uid=sa;password=xxx" /></appSettings>
    private SqlConnection conn = new SqlConnection(connStr);
    //增
    protected void add_Click(object sender, EventArgs e)
    {
        string sqlStr = "insert into 友情链接([外链名]) values ('测试')";
        execSql(sqlStr);
        queryTable();
    }
    //删
    protected void del_Click(object sender, EventArgs e)
    {
        string sqlStr = "delete 友情链接 where ID>9";
        execSql(sqlStr);
        queryTable();
    }
    //改
    protected void modify_Click(object sender, EventArgs e)
    {
        string sqlStr = "update 友情链接 set 外链名='测试2' where ID>9";
        execSql(sqlStr);
        queryTable();
    }
    //查
    protected void query_Click(object sender, EventArgs e)
    {
        queryTable();
    }
    //查询通用
    private void queryTable()
    {
        if (this.conn.State == ConnectionState.Closed)
        {
            this.conn.Open();
        }
        else if (this.conn.State == ConnectionState.Open)
        {
            this.conn.Close();
            this.conn.Open();
        }
        else if (this.conn.State == ConnectionState.Broken)
        {
            this.conn.Close();
            this.conn.Open();
        }
        string sqlStr = "select * from 友情链接";
        SqlDataAdapter da = new SqlDataAdapter(sqlStr, conn);
        DataTable dt = new DataTable();
        da.Fill(dt);
        conn.Close();
        Repeater1.DataSource = dt.DefaultView;
        Repeater1.DataBind();
    }
    //增删改通用
    private void execSql(string sqlStr)  
    {
        if (this.conn.State == ConnectionState.Closed)
        {
            this.conn.Open();
        }
        else if (this.conn.State == ConnectionState.Open)
        {
            this.conn.Close();
            this.conn.Open();
        }
        else if (this.conn.State == ConnectionState.Broken)
        {
            this.conn.Close();
            this.conn.Open();
        }
        SqlCommand cmd = new SqlCommand(sqlStr, conn);
        int res = cmd.ExecuteNonQuery();
        conn.Close();
    }