How to update DataGrid on click event?

I have the following code which updates the data base on a button click by calling a function additems.

static DataTable additems(string itema, string itemb, string itemc, string itemd)
   开发者_C百科     {
            DataTable listitems = new DataTable();
            listitems.Columns.Add("itema");
            listitems.Columns.Add("itemb");
            listitems.Columns.Add("itemc");
            listitems.Columns.Add("itemd");

            // Add new items
            listitems.Rows.Add(itema, itemb, itemc, itemd);

            return listitems;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // add to data grid
            dataGridView1.DataSource = additems("New text", "Almonds", "Butter", "Salt");
        }

I wanted the above code to create new data grid. And it works fine for single data.. but for multiple data how can i achieve such heights?

I have a new variable (not using any database). Whenever button1 is clicked this variable needs to be loaded to data table so that it can instantly add to datagridview1.

I need some concepts...

well, you could change the method sig to take a new parameter for the datatable ...

if that's null, create a new table like you do now ... if it's not null, simply add a new row to that existing table

//quick and dirty example

static DataTable additems(string itema, string itemb, string itemc, string itemd, DataTable foo)
{
    DataTable listitems = foo;
    if(foo == null)
    {
       listitems = new DataTable();
       listitems.Columns.Add("itema");
       listitems.Columns.Add("itemb");
       listitems.Columns.Add("itemc");
       listitems.Columns.Add("itemd");
    }

    // Add new items
    listitems.Rows.Add(itema, itemb, itemc, itemd);

    return listitems;
}

private void button1_Click(object sender, EventArgs e)
{
    // add to data grid

    dataGridView1.DataSource = additems("New text", "Almonds", "Butter", "Salt", (DataTable)dataGridView1.DataSource); 
}

you also might want to think about storing that datatable in a private field, instead of using (DataTable)dataGridView1.DataSource, but the question wasn't about good coding style ;)