插入或更新或删除后刷新datagridview而不选择新的sql查询

Question

我只是想澄清一下，我可以在插入或更新或删除后刷新 datagridview 而不再次选择新的 sql 查询吗？ 我已经用谷歌搜索了它，但仍然不知道这样做。

这是我的代码

private void button4_Click(object sender, EventArgs e)
    {
        employee();
    }

    public void employee()
    {
        DataTable dtclubroom = new DataTable();
        SqlCommand command = new SqlCommand();
        SqlDataAdapter adapter = new SqlDataAdapter(command.CommandText, myConnection);
        try
        {
            myConnection.Open();
            dtclubroom.Clear();
            command.Connection = myConnection;
            command.CommandText = "Select * from employee ";
            adapter.SelectCommand = command;
            adapter.Fill(dtclubroom);  
            dataGridView2.DataSource = dtclubroom;
        }
        catch (Exception ex)
        {
            MessageBox.Show("error" + ex);
        }
        finally
        {
            myConnection.Close();
        }
    }

    private void button5_Click(object sender, EventArgs e)
    {
        SqlCommand command2 = new SqlCommand();
        try
        {
            myConnection.Open();
            command2.CommandText = "insert into employee (name,id) values (@name,@id)";
            command2.Connection = myConnection;
            command2.Parameters.AddWithValue("@name","Leon");
            command2.Parameters.AddWithValue("@id", "002");
            command2.ExecuteNonQuery();
        }
        catch (Exception  exc)
        {
            MessageBox.Show(exc.Message);
        }
        finally
        {
            myConnection.Close();
        }
        employee() //<- refresh datagridview
    }

Button 4是加载数据，button 5插入数据也是加载数据。有没有办法在不再次调用employee() 方法的情况下刷新datagridview？

Answer 1

您可以通过多种方式做到这一点。

1. 将新插入的记录添加到您的数据表（您需要为此使用全局数据表变量）并使用此数据表刷新您的Grid View。
2. 可以将新插入的记录直接添加到Grid View

DELETE 和 UPDATE 也可以使用这些技术

这是您现有代码的想法 #1 的实现：

DataTable dtclubroom = new DataTable();

private void button4_Click(object sender, EventArgs e)
{
    employee();
}

public void employee()
{
    SqlCommand command = new SqlCommand();
    SqlDataAdapter adapter = new SqlDataAdapter(command.CommandText, myConnection);
    try
    {
        myConnection.Open();
        dtclubroom.Clear();
        command.Connection = myConnection;
        command.CommandText = "Select * from employee ";
        adapter.SelectCommand = command;
        adapter.Fill(dtclubroom);  
        dataGridView2.DataSource = dtclubroom;
    }
    catch (Exception ex)
    {
        MessageBox.Show("error" + ex);
    }
    finally
    {
        myConnection.Close();
    }
}

private void button5_Click(object sender, EventArgs e)
{
    SqlCommand command2 = new SqlCommand();
    try
    {
        myConnection.Open();
        command2.CommandText = "insert into employee (name,id) values (@name,@id)";
        command2.Connection = myConnection;
        command2.Parameters.AddWithValue("@name","Leon");
        command2.Parameters.AddWithValue("@id", "002");
        command2.ExecuteNonQuery();

        DataRow dr = dtclubroom.NewRow();
        dr["name"] = "Leon";
        dr["id"] = "002";
        dtclubroom.Rows.Add(dr);
    }
    catch (Exception  exc)
    {
        MessageBox.Show(exc.Message);
    }
    finally
    {
        myConnection.Close();
    }

    dataGridView2.DataSource = dtclubroom; //<- refresh datagridview
}

看看数据表声明被上移了，你需要把它放在你的类的顶部：

DataTable dtclubroom = new DataTable(); 

没有其他东西需要是全局的。