Hi there,

I am currently using a method from an earlier post (http://forums.asp.net/t/1358255.aspx) to validate on insert and update. In this post we are using the partial class and throwing a new exception.

Currently these validations show in a validation summary and not in-line.

The problem is that other validations applied via metadata on each column show up in-line.

I want to have all validations shown inline, is there anyway to do this? because otherwise it is very untidy.

Appreciate any feedback.

Unless the validation is done at column level

OnXXXChanging(string value)

 I thought the only way to do it at column level is by applying attributes in metadata.cs ?

But how can I entered values with values in the database when using attributes in metadata?

For

• Linq to SQL: implement the Partial methods OnXXXChanging event
• Entity Framework: http://msdn.microsoft.com/en-us/library/cc488527.aspx (I'm not well up on EF)

Hi,

Thanks for that it was what I was looking for.

One small problem though - it works fine on inserting but on updating a field it validates even when I haven't changed anything or when I have changed one field but not the other it still gives an error for both fields.

Does anybody know if there is another method similar to OnXXXChanging such as OnXXXUpdating ?

My code from metadata.cs is below:

[MetadataType(typeof(SupplierMetaData))]
    public partial class Supplier
    {
        partial void OnFCCSupplierIdentifierChanging(string value)
        {
            var Fcc = new ParentFccOnlineNettingDataContext();

            // FCCSupplierIdentifier
            var supplierid = Fcc.Suppliers.FirstOrDefault(c => c.FCCSupplierIdentifier ==  value);

          

            if (supplierid != null)
            {
                throw new ValidationException(String.Format("The Supplier Id {0} already exists. Please specify a different identifier.", value));
            }
          
        }

        partial void OnSupplierNameChanging(string value)
        {
            var Fcc = new ParentFccOnlineNettingDataContext();

            // SupplierName
            var suppliername = Fcc.Suppliers.FirstOrDefault(c => c.SupplierName == value);
           
            if (suppliername != null)
            {
                throw new ValidationException(String.Format("The Supplier Name {0} already exists. Please specify a different name.", value));
            }
        }

    }

If you have a look at the Extensibility Method Definitions: 

    #region Extensibility Method Definitions
    partial void OnLoaded();
    partial void OnValidate(System.Data.Linq.ChangeAction action);
    partial void OnCreated();
    partial void OnCategoryIDChanging(int value);
    partial void OnCategoryIDChanged();
    partial void OnCategoryNameChanging(string value);
    partial void OnCategoryNameChanged();
    partial void OnDescriptionChanging(string value);
    partial void OnDescriptionChanged();
    partial void OnPictureChanging(System.Data.Linq.Binary value);
    partial void OnPictureChanged();
    #endregion  

As you can see these are the only partial methods you can implements 

CategoryName field of Northwind DB: 

[Column(Storage="_CategoryName", DbType="NVarChar(15) NOT NULL", CanBeNull=false)]
public string CategoryName
{
	get
	{
		return this._CategoryName;
	}
	set
	{
		if ((this._CategoryName != value))
		{
			this.OnCategoryNameChanging(value);
			this.SendPropertyChanging();
			this._CategoryName = value;
			this.SendPropertyChanged("CategoryName");
			this.OnCategoryNameChanged();
		}
	}
}

As you can see these partial methods are called every time the setter is called and of course because it's a web app the get called every time you edit or create an item.

So the best approach is to check the value to see if it is the same as the property and then exit.