WinForm----DataGridview---连接数据库，以及双击一条数据，显示信息到Label控件，也可以是TextBox控件。

最终效果：

代码：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using System.Configuration;
 using System.Data.SqlClient;

 namespace Test
 {
     public partial class Form1 : Form
     {
         string constring = ConfigurationManager.ConnectionStrings["constring"].ConnectionString;

         public Form1()
         {
             InitializeComponent();

             data();
         }

         public void data()
         {
             using (SqlConnection con = new SqlConnection(constring))
             {
                 con.Open();

                 string Sql = "select * from tb_Frinfo";

                 DataTable dt = new DataTable();

                 SqlDataAdapter dap = new SqlDataAdapter(Sql, con);

                 dap.Fill(dt);

                 this.dataGridView1.DataSource = dt;
             }
         }

         private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
         {
             this.label1.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label2.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label3.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label4.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label5.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label6.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label7.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
             this.label8.Text = this.dataGridView1.SelectedRows[].Cells[].Value.ToString();
         }

     }
 }