Question

I had a combobox in a Windows Forms form which retrieves data from a database. I did this well, but I want to add first item <-Please select Category-> before the data from the database. How can I do that? And where can I put it?

public Category()
{
    InitializeComponent();
    CategoryParent();

}

private void CategoryParent()
{
    using (SqlConnection Con = GetConnection())
    {
        SqlDataAdapter da = new SqlDataAdapter("Select Category.Category, Category.Id from Category", Con);
        DataTable dt = new DataTable();
        da.Fill(dt);
        CBParent.DataSource = dt;
        CBParent.DisplayMember = "Category";
        CBParent.ValueMember = "Id";
    }
}

Answer 1

You could either add the default text to the Text property of the combobox like this (preferred):

CBParent.Text = "<-Please select Category->";

Or, you could add the value to the datatable directly:

da.Fill(dt);
DataRow row = dt.NewRow();
row["Category"] = "<-Please select Category->";
dt.Rows.InsertAt(row, 0);
CBParent.DataSource = dt;