I've created a UserControl with a DataGridView. In my code I add this UserControl to a TabControl-TabPage on a Form. This works well.

Now I want to do a double click on the DataGridView of the UserControl, select the row as an object and use this data on another TabPage which is on the initial Form.

How can I get access to the UserControl event an my Form?

I tried it that way(first answer) How to use UserControl but I can't use it on my Form. So this is not working.

And how to do a DataGridViewCellEvent to use?

EDIT: I tried the following way now: UserControl:

 public partial class ucData : UserControl
    {
        public ucData(string Number)
        {
            InitializeComponent();
public string Data
        {
            get { return textBox1.Text; }
            set { textBox1.Text = value; }
        }
        public event EventHandler DataAvailable;
        /// <summary>
        /// Called to signal to subscribers that new data is available
        /// </summary>
        /// <param name="e"></param>
        protected virtual void OnDataAvailable(EventArgs e)
        {
            EventHandler eh = DataAvailable;
            if (eh != null)
            {
                eh(this, e);
            }
        }
....

...
private void dataGridView_CellDoubleClick(object sender, EventArgs e)
        {
            OnDataAvailable(null);
        }

And on my Main Form:

...
 void Test()
        {
            UserControls.ucData uc = new ucData(null);
            uc.DataAvailable  = new EventHandler(child_DataAvailable);
            uc.Data = "Hello!";
        }
        void child_DataAvailable(object sender, EventArgs e)
        {
            UserControls.ucData child = sender as UserControls.ucData;
            if (child != null)
            {
                MessageBox.Show(child.Data);
            }
        }
...

But if I do a doubleClick on the UserControl no MessageBox will appear. Why? What is wrong? Can anyone help please.

CodePudding user response：

Try this:

UserControl

public partial class UserControl1: UserControl
{
    public event DataGridViewCellEventHandler dataGridView1_CellDoubleClickEvent;

    public UserControl1()
    {
        InitializeComponent();
    }

    private void UserControl1_Load(object sender, EventArgs e)
    {
        this.dataGridView1.CellDoubleClick  = dataGridView1_CellDoubleClickEvent;
    }

    private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
    {
        dataGridView1_CellDoubleClickEvent?.Invoke(this.dataGridView1, e);
    }
}

Form

private void Form1_Load(object sender, EventArgs e)
    {
        userControl11.dataGridView1_CellDoubleClickEvent  = new DataGridViewCellEventHandler(dataGridView1_CellDoubleClick);
     }        

    private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
    {
        //Your code for the "dataGridView_CellDoubleClick" event
    }

CodePudding user response：

 public class CustomerRepository : ICustomerRepository
    {
        public IEnumerable<Customer> GetAllCustomer()
        {
            using (IDbConnection db = new MySqlConnection(AppConnection.ConnectionString))
            {
                string q = @"SELECT ....";
                return db.Query<Customer>(q, commandType: CommandType.Text);
            }
        }
}

I use the repository in my UserControl to show all data.

The error message: System.NullReferenceException: Object reference not set to an instance of an object. ...AppConnection..cctor()

Here my AppConnection:

public static class AppConnection
    {
        public static string ConnectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;
}