Question

Using Windows Forms, two link labels are created dynamically. When the user clicks on anyone of links labels, one dynamic form is created. In that form I created one data grid, a text box and a button placed dynamically (in that dynamic form). Now I want to access the dynamic data grid in the dynamic button click event. How can I do that?

private void Users_Load(object sender, EventArgs e)
{
    da = new SqlDataAdapter("Usp_Get_Employees", con);
    ds = new DataSet();
    da.Fill(ds);

    if (ds.Tables[0].Rows.Count > 0)
    {
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        {
            string somecode = i.ToString() + ds.Tables[0].Rows[i]["eid"].ToString();
            LinkLabel  lbluser  = new LinkLabel();
            lbluser.Name =  ds.Tables[0].Rows[i]["eid"].ToString();
            lbluser.Text = ds.Tables[0].Rows[i]["ename"].ToString();
            lbluser.Location = new System.Drawing.Point(40, i * 40);
            lbluser.Size = new System.Drawing.Size(50, 30);
            Controls.Add(lbluser);
            lbluser.Click += new EventHandler(lbluser_Click);
        }
    }
}


void lbluser_Click(object sender, EventArgs e)
{
    LinkLabel lnkClis = (LinkLabel)sender;
    Form frm = new Form();
    frm.Name = lnkClis.Name;
    frm.Text = lnkClis.Text;
    frm.Show();

    DataGrid dtgrd = new DataGrid();
    dtgrd.Location = new System.Drawing.Point(10, 1 * 40);
    dtgrd.Name = lnkClis.Name;
    names = lnkClis.Name;

    TextBox tx = new TextBox();

    tx.Location = new System.Drawing.Point(10, 5 * 40);
    tx.Size = new Size(80, 30);
    tx.Multiline = true;
    tx.LostFocus += new EventHandler(tx_LostFocus);

    Button btn = new Button();
    btn.Location = new System.Drawing.Point(10, 7 * 40);
    btn.Size = new System.Drawing.Size(50, 30);
    btn.Name = lnkClis.Name;
    btn.Click += new EventHandler(btn_Click);

    frm.Controls.Add(dtgrd);
    frm.Controls.Add(tx);
    frm.Controls.Add(btn);
}

// Now I am trying to access the data grid in the btn_click event

void btn_Click(object sender, EventArgs e)
{
    Button btsave = (Button)sender;
    string eid = btsave.Name;

    object grd = btsave.Parent.Controls.Find("dtgrd", true).FirstOrDefault();

    ((DataGrid)grd).DataSource = ds.Tables[0];
}

Now I am getting an error object set of instances of an object at:

((DataGrid)grd).DataSource = ds.Tables[0];

Answer 1

The exception message you have written:

Now I am getting an error object set of instances of an object at

makes no sense, but it looks like

Object reference not set to an instance of an object

If this is the case, I think the error lays in Find method call. According to documentation:

Searches for controls by their Name property and builds an array of all the controls that match.

In your button click handler you assume that grid is called dtgrd, but while you create a grid you name it like this:

dtgrd.Name = lnkClis.Name;

it will suffice if you change this line to:

dtgrd.Name = "dtgrd";

Having said that, you should consider using an anonymous method for the button click handler. It will eliminate need for calling the Find method in the first place.

 void lbluser_Click(object sender, EventArgs e)
{
   //...
    DataGrid dtgrd = new DataGrid();
   //...
    Button btn = new Button();
   //...
    btn.Click += (sender,args)=> dtgrd.DataSource = ds.Tables[0];