SQLDataReader读取函数不返回任何内容 [英] SQLDataReader read function not returning anything

问题描述

你好我们有问题SQLDataReader的读取功能没有返回anuthing。请帮我弄清问题。



我从这个函数传递数据，顺便说一句是deleteEntry类

Hello guys I am having a problem the read function of SQLDataReader is not returning anuthing. Please help me to figure out the problem.

I am passing data from this function which by the way is of deleteEntry class

string name = this.textBox1.Text;
            string connstring = @"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Gardezi\Documents\Visual Studio 2012\Projects\homeWork2\homeWork2\Database1.mdf;Integrated Security=True";
            SqlConnection con = new SqlConnection(connstring);
            string query = "Select * from diaryDB where Title=@name";
            SqlCommand com = new SqlCommand(query, con);
            SqlParameter p = new SqlParameter("name", name);
            com.Parameters.Add(p);
            con.Open();
            SqlDataReader d =  com.ExecuteReader();
            deleteResult r = new deleteResult(d);
            con.Close();
            r.Show();

然后在类deleteResult的构造函数中我正在初始化组合框。

Then here in constructor of class deleteResult I am intializing the combo box.

public deleteResult(SqlDataReader d)
        {
            
            InitializeComponent();
            while (d.Read())
            {
                
                this.comboBox1.Items.Add((d["title"] + "-" + d["description"]).ToString());
            }
        }

但是当我尝试从数据库中获取数据时，它成功获取数据但是程序永远不会进入我试图读取数据的循环

But when I try to get data from the DB it successfully aquires the data but the program never enters the loop where I am trying to read the data

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string name = this.comboBox1.SelectedItem.ToString();
        string[] arr = name.Split('-');
        string p1 = arr[1];
        string connstring = @"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Gardezi\Documents\Visual Studio 2012\Projects\homeWork2\homeWork2\Database1.mdf;Integrated Security=True";
        SqlConnection con = new SqlConnection(connstring);
        string query = "Select * from diaryDB where Description=@p1";
        SqlCommand com = new SqlCommand(query, con);
        SqlParameter p = new SqlParameter("p1", name);
        com.Parameters.Add(p);
        con.Open();
        SqlDataReader d = com.ExecuteReader();
        int   p11 = d.FieldCount;
        MessageBox.Show(""+p11);
        while (d.Read())
        { 
            this.textBox1.Text = d["Title"].ToString();
            this.richTextBox1.Text = d["Description"].ToString();
            this.pictureBox1.Image = Image.FromFile(d["pic"].ToString());
        }
        con.Close();
        query = "delete from diaryDB where Description=@p1";
        com = new SqlCommand(query, con);
        p = new SqlParameter("p1", p1);
        com.Parameters.Add(p);
        con.Open();
        com.ExecuteNonQuery();
        con.Close();
   }

推荐答案

SqlParameter p = new SqlParameter（p1，name）; - 应该名称是 p1 ？





如果我不清楚...

SqlParameter p = new SqlParameter（p1， name p1 ）;

SqlParameter p = new SqlParameter("p1", name); -- should name be p1 ?


In case I was unclear...
SqlParameter p = new SqlParameter("p1", name p1);

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