ASP鏈接SQL SERVER增刪查改操作

直接上碼：

//數據庫空間
using System.Data.SqlClient;
using System.Configuration;

public partial class _Default : System.Web.UI.Page
{
    int i = 1;
    protected void Page_Load(object sender, EventArgs e)
    {
        string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection sqlconn = new SqlConnection(sqlconnstr);
        SqlCommand sqlcommand = new SqlCommand();
        sqlcommand.Connection = sqlconn;
        sqlconn.Open();
        sqlcommand.CommandText = "select * from userdata";
        SqlDataReader sqldatareader = sqlcommand.ExecuteReader();
        Label1.Text= "<table class='table table-hover'>";
        Label1.Text+= "<thead><tr><td> ID </td><td> 姓名 </td><td> 年齡 </td><td> 電話 </td></tr></thead> ";
        
        while(sqldatareader.Read())
        {
            Label1.Text += "<tr><td class='success'>" + (i++)+ "</td>";
            Label1.Text += "<td class='warning'>" + sqldatareader.GetString(1) + "</td>";
            Label1.Text += "<td class='danger'>" + sqldatareader.GetInt32(2) + "</td>";
            Label1.Text += "<td class='active'>" + sqldatareader.GetString(3) + "</td></tr>";
        }
        Label1.Text += "</table>";
        sqlcommand = null;
        sqlconn.Close();
        sqlconn = null;


    }

    protected void Add_Click(object sender, EventArgs e)
    {
        string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection sqlconn = new SqlConnection(sqlconnstr);
        SqlCommand sqlcommand = new SqlCommand();
        sqlcommand.Connection = sqlconn;
        sqlcommand.CommandText = "insert into userdata(id,name,age,phone) values(@id,@name,@age,@phone)";
        sqlcommand.Parameters.AddWithValue("@id", i);
        sqlcommand.Parameters.AddWithValue("@name", Username.Text);
        sqlcommand.Parameters.AddWithValue("@age", Age.Text);
        sqlcommand.Parameters.AddWithValue("@phone", Phone.Text);
        try
        {
            sqlconn.Open();
            sqlcommand.ExecuteNonQuery();
            Response.Redirect(Request.Url.ToString());
        }
        catch(Exception ex)
        {
            Label1.Text = "添加失敗！"+ex.Message;
        }
        finally
        {
            sqlcommand = null;
            sqlconn.Close();
            sqlconn = null;
        }
        
    }

    protected void Delete_Click(object sender, EventArgs e)
    {
        string sqlconnstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection sqlconn = new SqlConnection(sqlconnstr);
        SqlCommand sqlcommand = new SqlCommand();
        sqlcommand.Connection = sqlconn;
        sqlcommand.CommandText = "delete from userdata where id=@id";
        string num = ID1.Text;
        sqlcommand.Parameters.AddWithValue("@id", num);
        try
        {
            sqlconn.Open();
            int intDeleteCount=sqlcommand.ExecuteNonQuery();
            if (intDeleteCount > 0)
            {
                sqlcommand.CommandText = "UPDATE userdata set id=id-1 where id>@id2;";
                sqlcommand.Parameters.AddWithValue("@id2", num);
                sqlcommand.ExecuteNonQuery();
                Response.Redirect(Request.Url.ToString());
            }
            else
            {
                Response.Write("<script>alert('未找到該記錄！');</script>");
            }
        }
        catch (Exception ex)
        {
            Label1.Text = "刪除失敗！" + ex.Message;
        }
        finally
        {
            sqlcommand = null;
            sqlconn.Close();
            sqlconn = null;
        }
    }
}

web.config\

 <connectionStrings>
      <add name="ConnectionString" connectionString="Data Source=.;Initial Catalog=asp-test;User ID=;Password=;Integrated Security=True" providerName="System.Data.SqlClient"/>
    </connectionStrings>