如果在另一个文本框中输入值，如何在一个文本框中检索值&反之亦然 [英] how to retrieve values into one textbox if entered into other textbox & viceversa

问题描述

先生您好，

我正在用C#在Windows窗体应用程序中创建.
我创建了三个标签的名字，中间名，姓氏.在这些标签的前面将有文本框&下面的一个按钮称为搜索"按钮.我创建了一个表，其中的字段称为名字，中间名，姓氏和名字.插入值.现在在输出窗口中，如果我输入名字& ;，点击搜索按钮，数据将被检索到其他文本框中，中间名，姓氏.

这是我的代码，我认为我们需要更改查询:

Hello sir,

I am creating in windows form appliacation in C#.
I created three labels first name,middle name,last name. Infront of those labels there will be textboxes & one button below called "Search" Button. I had created a table in which fields called first name,middle name,last & inserted values. Now in the output window ,if i give a firstname & hit a search button,the data as to be retrived into other textboxes-middle name,last name.

this my code,i think we need to change the query:

//search button below.
 private void button1_Click(object sender, EventArgs e)
        {
            con = new SqlConnection("Data Source=CBP\\SQLEXPRESS;Initial Catalog=ECG;Integrated Security=True");
            con.Open();
            com = new SqlCommand("select middle,last from  Table2 where first= '"+ textBox1.Text.Trim()+"'",con);
            rdr = com.ExecuteReader();
            bool temp = false;
            while (rdr.Read())
            {

                //textBox1.Text = rdr.GetString(0);
                textBox1.Text = rdr[0].ToString().Trim();//ToString();// GetString(1);
                textBox2.Text = rdr[1].ToString().Trim();
                //textBox4.Text = rdr.GetString(3);
                //textBox5.Text = rdr.GetString(4);
                //textBox6.Text = rdr.GetString(5);
                //textBox7.Text = rdr.GetString(6);
                //textBox8.Text = rdr.GetString(7);
                //textBox9.Text = rdr.GetString(8);
                //textBox10.Text = rdr.GetString(9);
                temp = true;

            }
            
            if (temp == false)
                MessageBox.Show("not found");
            con.Close();

            con.Open();
            ds = new DataSet();
            da = new SqlDataAdapter("select * from Table2", con);
            da.Fill(ds, "Table2");
            con.Close();


        }

如何实现此功能.
请帮我

谢谢
Pradeep CBZ

How to achieve this sir.
please do help me

Thanks
Pradeep CBZ

推荐答案

首先，最好使用参数化查询，而不是像这样串联字符串

First off, it is best to use a parameterised query rather than concatenating strings like this

com = new SqlCommand("SELECT middle, last FROM  Table2 WHERE first = @firstName", con);
com.Parameters.AddWithValue(@firstName", textBox1.Text.Trim());

然后，您可以使用dr.HasRows而不是使用像这样的临时布尔变量:-

Then you can use dr.HasRows instead of using a temp bool variable like this:-

if(dr.HasRows)
{
  while(dr.Read())
  {
    txtLast.Text = (string)dr[0];
    txtMiddle.Text = (string)dr[1];
  }
  dr.Close();
}
else
{
  MessageBox.Show("Not found !");
}

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