将新增加到gridcontrol devexpress

Question

I am trying add a new row into datagridview with the button click for learning purposes. When I click the button, it deletes the old data and add the new row. But I want to append it to the grid

here is my form_load function which gets the data from the database and fill the grid.

private void Form1_Load(object sender, EventArgs e)
    {
        SqlConnection connection = new SqlConnection("Data Source=ARIF-BILGISAYAR;Initial Catalog=RotanetLocal;Persist Security Info=True;User ID=sa;Password=12345");
        SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM TestTable", connection);
        DataSet sourceDataSet = new DataSet();
        adapter.Fill(sourceDataSet);
        gridControl1.DataSource = sourceDataSet.Tables[0];

    }

and here is my button event which is supposed to append a row into the grid, but it deletes the old data and inserts the new one

private void btn_update_Click(object sender, EventArgs e)
    {
        DataTable dtOperation = new DataTable();

        var myOriginalDataSource = (DataTable)gridControl1.DataSource;
        var dr = myOriginalDataSource.NewRow();
        dr["id"] = 1;
        dr["name"] = "Gelen Havale";
        dr["lname"] = "Gelen Havale";
        dtOperation.Rows.Add(dr);

        gridControl1.Refresh();
    }

my btn_update_click function is now trying to create a row and append it to the old data. but it now crashes. It says taht this row belongs to another table. how can I fix that?

Answer 1

It looks like you are completely replacing the DataSource property which will tell the control to completely re-render.

Add the new row to the existing DataSource and then call the Refresh() method.

On the other-hand if you are using WPF move away from using DataTable and start using an ObservableCollection<T> instead.

    private void btn_update_Click(object sender, EventArgs e)
    {
        var myOriginalDataSource = gridControl1.DataSource;
        var dr = myOriginalDataSource.NewRow();

        dr["id"] = 1;
        dr["name"] = "Gelen Havale";
        dr["lname"] = "Gelen Havale";

        gridControl1.Refresh();
    }

The Refresh() is psudocode as I don't know the DevExpress WinForms controls very well.

Answer 2

You need to change your code to this:

private void btn_update_Click(object sender, EventArgs e)
{
    var myOriginalDataSource = (DataTable)gridControl1.DataSource;
    var dr = myOriginalDataSource.NewRow();

    dr["id"] = 1;
    dr["name"] = "Gelen Havale";
    dr["lname"] = "Gelen Havale";

    gridControl1.Refresh();
}

I think it would be worth spending some time reading up on Object Orientation Principles

You were still creating a new DataTable needlessly and adding the row to that instance rather than the DataTable already data-bound to your grid control instance.

Answer 3

你已经创建了一个新的DataTable并与它绑定，这就是为什么..