How to generate GUIDs automatically while creating

I am having an SQL Server database, which is having a lots of table. Each of the table is having a primary column, which in fact is a GUID column. I have created new ASP.NET Dynamic data site to manage these tables. The problem is that, the GUIDs are not being generated and that's why the site breaks for all tables.

I tried by adding "newID()" in SQL table, but it still fails. I believe I need to somehow do changes in code. I believe this might be an issue faced by many developers working with ASP.Net Dynamic site.. Any idea of how to fix this?

回答1:

I think I cheated but I just created a new GUID Field template. To use create the extension metadata for your class. Shortened version shown here. And associate it with your class.

Then add the GUID.ascx and GUID_Edit.ascx to your project. When you insert a new record a GUID will be generated and show up read only in your form. Key is making the UIHint to be a GUID type.

Code below...

--- EventCalendarMetadata.cs

namespace DFEventsWeb
{
    [MetadataType( typeof ( EventCalendar_Metadata ) )  ]
    public partial class EVENT_CALENDAR
    {
        [DisplayName("EVENTS")]
        private abstract class EventCalendar_Metadata
        {
            [Display(Name = "ID")]
            [UIHint("GUID")]
            public object EVENT_ID { get; set; }

.... other fields removed ...
        }
    }
}

--- GUID.ascx

<%@ Control Language="C#" CodeBehind="GUID.ascx.cs" Inherits="DFEventsWeb.GUID" %>
<asp:Literal runat="server" ID="Literal1" Text="<%# FieldValueString %>" />

--- GUID.ascx.cs namespace DFEventsWeb {

    public partial class GUID : System.Web.DynamicData.FieldTemplateUserControl
    {
        private const int MAX_DISPLAYLENGTH_IN_LIST = 100;

        public override string FieldValueString
        {
            get
            {
                string value = base.FieldValueString;
                if (ContainerType == ContainerType.List)
                {
                    if (value != null && value.Length > MAX_DISPLAYLENGTH_IN_LIST)
                    {
                        value = value.Substring(0, MAX_DISPLAYLENGTH_IN_LIST - 3) + "...";
                    }
                }
                return value;
            }
        }

        public override Control DataControl
        {
            get
            {
                return Literal1;
            }
        }
    }
}

--- GUID_Edit.ascx

<%@ Control Language="C#" CodeBehind="GUID_Edit.ascx.cs" Inherits="DFEventsWeb.GUID_EditField" %>
<asp:Literal ID="Literal1" runat="server" Text='<%# OVERRIDE_GUID %>'></asp:Literal>

--- GUID_Edit.ascx.cs

namespace DFEventsWeb
{
    public partial class GUID_EditField : System.Web.DynamicData.FieldTemplateUserControl
    {
        const int MAX_TEXT_COLUMN_SIZE = 200; // jeh

        string m_GUIDString;
        public string OVERRIDE_GUID 
        {
            get { return m_GUIDString; }
            set { m_GUIDString = value; }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
        }

        protected override void OnDataBinding(EventArgs e)
        {
            base.OnDataBinding(e);
            OVERRIDE_GUID = ( FieldValueEditString.Length <= 0 ? System.Guid.NewGuid().ToString() : FieldValueEditString );
        }

        protected override void ExtractValues(IOrderedDictionary dictionary)
        {
            dictionary[Column.Name] = ConvertEditedValue(Literal1.Text);
        }

        public override Control DataControl
        {
            get
            {
                return Literal1;
            }
        }
    }
}

回答2:

I have added following code in "Inserting" event of a FormView Control in ~PageTemplates\Insert.aspx.

e.Values.Add("Id", Guid.NewGuid());

As all my tables have a consistent naming convension as Id represents PK column, I am fine to use this hard-coded column name, or else, you may need to write appropriate logic to find PK column.