First step is to open a new Project and name it as “DataGridView_Application”, Next step is to create a Form that contains DataGridView control as shown below.

As soon as we will populate data from the database in Gridview while selecting of any fields in the gridview another form display as here we named it as “NewForm”.  To show data in another from we have to create another form as “New Form” with four Fields as textbox and two Update Buttons; as shown below.

code for accept a data from the database and display a record in the data gridview as soon as page load so we have to write a code under form_load area as shown below.

  privatevoid Update_Load(object sender, EventArgs e)
         {
//create a connection and pass connection string along with parameters.
        SqlConnection con =  newSqlConnection("server=abc-PC1\\sqlexpress; uid=sa; password=sa; database=Mind");
           
            con.Open();//connection open
//creating dataadapter object and executing query inside it.
            SqlDataAdapter sda = newSqlDataAdapter("select * from Employee",con);
//craeting datatable object as dt
            DataTable dt = newDataTable();
            sda.Fill(dt);//fill data in dataadapter 
            dataGridView1.DataSource = dt;
//setting datasource of datagridview to object of datatable
  
        }

On double click of selected record from datagridview we are going to populate record to our “NewForm” Please check blow lines of code.

privatevoid dataGridView1_CellDoubleClick(object sender,  DataGridViewCellEventArgs e)
         {
            int id =  Convert.ToInt32(dataGridView1.Rows[e.RowIndex].Cells[0].Value);
            NewForm nf =  newNewForm(id);//creating Object of NewForm and passing the “id”
            nf.ShowDialog();//show new form
         }

Next step is code area of the “newform” and declare id global.

Code

publicpartialclassNewForm : Form
    {
        SqlConnection con;//global declaration
        SqlDataReader rdr;//global declaration
        SqlDataReader rdr1;//global declaration
        int nID;       
        public NewForm(int ID) //constructor is passing            
         {
            InitializeComponent();
            con = new SqlConnection("server=abc-PC1\\sqlexpress; uid=sa; password=sa; database=Mind");
            nID = ID;
         }  
  
privatevoid NewForm_Load(object sender, EventArgs e)
  {
    con.Open();
//creating sqlcommand object and Passing query
SqlCommand cmd = newSqlCommand("select * from Employee where Employee_id=" + nID, con);
//execting data reader
rdr = cmd.ExecuteReader();
rdr.Read();//reading datareader
string a = rdr[0].ToString();
txtID.Text = a;
txtName.Text = rdr[1].ToString();
txtAddress.Text = rdr[2].ToString();
txtPhoneno.Text = rdr[3].ToString();
txtage.Text = rdr[4].ToString();
rdr.Close();//close the reader
}

As soon as we will populate data from the database in a datagridview we have to update the various records which is displaying on the newForm with the help of Update Button and also conferming with the help of MessageBox “wether do you want to update the record or not.

Code for this  is shown below.

privatevoid btbUpdate_Click(object sender, EventArgs e)
         {
            try
            {
//message box shows wether do you want to update the record or not 
                if (MessageBox.Show("Do you want to update record?", "update",  MessageBoxButtons.YesNo) == DialogResult.Yes)
                {
//query for updating record ina sqlcommand
                    SqlCommand cmd = newSqlCommand("UPDATE employee SET Employee_id='" + txtID.Text + "',Employee_name='" + txtName.Text + "',Employee_address='" + txtAddress.Text + "',Employee_phoneno='" + txtPhoneno.Text + "',Employee_age='" + txtage.Text + "'where Employee_id='" + nID + "'", con);
                    rdr1 = cmd.ExecuteReader();
                    con.Close();
                    this.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);

Output shows below as soon as page load data populates from the database in a gridview as shown below in the output.

As soon as we click any of the fields newform will display as shown below along with their records in the DataGrid.

As you click update button it will ask a confirmation dialog box whether you want to update the record or not if u have pressed yes then records updated as shown below with the help of arrow.