Question

我有两种表单Form1和Form2。 Form1上有DataTable，它连接到MySql数据库。我在Form1上创建了一个新的呼叫，然后打开Form2，其中有一些字段需要填写。然后按保存呼叫，这会更新数据库。

我遇到的问题是它何时保存到数据库并关闭Form2它没有出现在Form1上，除非我关闭程序并重新打开它。如何让DataTable刷新？

以下是Form1代码

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            string connectionString = "datasource=localhost;database=***;username=***;password=***;";
            string query = "select call_ref, opened, contact, it, summary  from helpdesks;";
            MySqlConnection connection = new MySqlConnection(connectionString);
            MySqlCommand command = new MySqlCommand(query, connection);
            connection.Open();
            MySqlDataAdapter adapter = new MySqlDataAdapter();
            adapter.SelectCommand = command;
            DataTable dTable = new DataTable();
            adapter.Fill(dTable);
            dataGridView1.DataSource = dTable;
            connection.Close();
        }

        public void viewData(object sender, DataGridViewCellEventArgs e)
        {
            Form2 secondForm = new Form2();
            secondForm.Show();

            string connectionString = "datasource=localhost;***;username=***;password=***;";
            string query = "select * from users where id = " + this.dataGridView1.CurrentRow.Cells[0].Value + ";";
            MySqlConnection connection = new MySqlConnection(connectionString);
            MySqlCommand command = new MySqlCommand(query, connection);
            connection.Open();

            MySqlDataReader reader = command.ExecuteReader();
            while(reader.Read())
            {
                secondForm.textBox1.Text = reader.GetString("call_ref");
            }
            connection.Close();
        }

        private void newCallBtn_Click(object sender, EventArgs e)
        {
            Form2 secondForm = new Form2();
            secondForm.Show();
        }
    }

这是我的Form2代码：

public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void saveCallBtn_Click(object sender, EventArgs e)
        {
            string connectionString = "datasource=localhost;database=***;username=***;password=***;";
            string query = "INSERT INTO helpdesks(contact, opened)VALUES('" + textBox2.Text + "',STR_TO_DATE('" + DateTime.Now + "','%d/%m/%Y %h:%i:%s %p'));";
            MySqlConnection connection = new     MySqlConnection(connectionString);
            MySqlCommand command = new MySqlCommand(query, connection);
            MySqlDataReader reader;
            connection.Open();
            reader = command.ExecuteReader();
            MessageBox.Show("Call Saved");
            connection.Close();
        }
   }

Answer 1

您可以使用FormClosedEventArgs。

private void newCallBtn_Click(object sender, EventArgs e)
        {
            Form2 secondForm = new Form2();
            secondForm.FormClosed += new FormClosedEventHandler(Form2_Closed);
            secondForm.Show();
        }

在Form1中添加：

private void Form2_Closed(object sender, FormClosedEventArgs e)
        {
          // here update DataTable

        }

在另一个表单上更新数据库后刷新另一个表单上的数据表中的数据

1 个答案: