In asp.net dynamic data, how to use UIHint to create a auto-fill field?

Question

I'm using asp.net dynamic data. There is a field I want to auto fill for users. The file is user name which can be obtained with integrated windows authentication.

I created a Field Template and it works in Insert mode, but in Update mode, once another user updates the record, the new user name should be saved, but it didn't.

Answer 1

I found a solution and I want to share it.

Apply UIHint for the entity field:

[UIHint("UserName")]
public object Name { get; set; }

Create a a new FieldTemplate:

<asp:TextBox ID="TextBox1" runat="server" ReadOnly="true" BorderStyle="None"
BackColor="Transparent" Text='<%# FieldValueEditString %>'></asp:TextBox>

Code behind for FieldTemplate:

public partial class UserName_EditField : FieldTemplateUserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {
        SetUpValidator(RequiredFieldValidator1);    
        EditFieldTemplateUserControl.InsertHelpText(this);
    }

    protected override void OnDataBinding(EventArgs e)
    {
        base.OnDataBinding(e);

        TextBox1.Visible = true;
    }

    protected string UserName
    {
        get
        {
            var name = this.Page.User.Identity.Name.ToString();
            return name;
        }
    }

    protected override void ExtractValues(IOrderedDictionary dictionary)
    {
        if (Page.IsPostBack)
        {// only assign value when user posts back.
            this.TextBox1.Text = this.UserName.ToUpper();
            dictionary[Column.Name] = ConvertEditedValue(TextBox1.Text);
        }
    }

    public override Control DataControl
    {
        get
        {
            return TextBox1;
        }
    }
}