这是一个向第一列使用AutoIncrement的数据表添加新行的示例：

定义表结构：

  Dim dt As New DataTable 
 dt。 Columns.Add（ID）
 dt.Columns.Add（Name）
 dt.Columns（0）.AutoIncrement = True 
 

添加新行：

  Dim R As DataRow = dt .NewRow 
 R（Name）= txtName.Text 
 dt.Rows.Add（R）
 DataGridView1.DataSource = dt 
 pre> 
I have a form with a textbox and a add button. 

user can write a name down on the textbox and click add button. it will save in a datatable with auto ID. 
after that, the textbox is cleared and the user can write another name on the text box and click the button. 
this should add to the existing datatable on memory with existing ID + 1.
show on the gridview. (this is just for display purpose to confirm it works)
I have a datatable like this. 
    Button1.click() event

    Dim name = txtname.Text
    Dim dt As New DataTable
    dt.Columns.Add("ID", GetType(Integer))
    dt.Columns.Add("Name", GetType(String))
    Dim N As Integer = dt.Columns("ID").AutoIncrement
    dt.Rows.Add(N, name)
    GridView1.DataSource = dt
    GridView1.DataBind()
    txtname.Text = ""
At the moment I have sometime like the code above. in the real program, it is not just name and it is not just one datatable so i just mock up some code.

and this code for aspx.
        <asp:TextBox ID="txtname" runat="server">
        </asp:TextBox><asp:Button ID="Button1" runat="server" Text="Button" />
        <asp:GridView ID="GridView1" runat="server">
        </asp:GridView>
can anyone advice me how to do it ? i understand my code is crapped and not correct but i just have to put some code so that you guys not need to work from scratch for me. 

Thanks so much. 
Here is an example of adding a new row to a datatable that uses AutoIncrement on the first column:

Define the table structure:
    Dim dt As New DataTable
    dt.Columns.Add("ID")
    dt.Columns.Add("Name")
    dt.Columns(0).AutoIncrement = True
Add a New row:
    Dim R As DataRow = dt.NewRow
    R("Name") = txtName.Text
    dt.Rows.Add(R)
    DataGridView1.DataSource = dt