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AppContextRegisterEmbeddedFunction Method (String, String, String)

Registers an embedded function for use in SQL statments. The function name should not include the leading lowercase 'fn' associated with embedded functions.

See EmbeddedParser for more information on embedded functions.

Embedded functions are automatically resolved for both DefaultValues on Field objects and Filters on Mapper objects.

Normally, you register an extension to run at startup and register custom functions in the ExtensionEvents.ApplicationAfterLoad event.

Namespace:  NetQuarry
Assembly:  EAP.Core (in EAP.Core.dll) Version: 2.0.0.0 (4.6.8.0)
Syntax
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public void RegisterEmbeddedFunction(
	string functionName,
	string replacementValue,
	string description
)

Parameters

functionName
Type: SystemString
The name of the function. The name should not include the leading 'fn.'
replacementValue
Type: SystemString
The replacement value.
description
Type: SystemString
The description of the function.

Implements

IAppContextRegisterEmbeddedFunction(String, String, String)
Examples
The following example extension event handler registers several functions loaded based on the user ID set during authentication.
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public override void AfterLoad(IAppContext sender, EAPEventArgs e)
{
    string      dealerID = iLuxCars.Common.EmailHelper.GetUserDealerID(sender);
    IDatabase   db = sender.Databases["DealerTrac"];
    if (db != null)
    {
        using (IDataReader dr = db.OpenDataReader("SELECT dealer_id, dealership_id, dealership_nm FROM dealer_user_dealership_view WHERE user_id = !fnUserID$()"))
        {
            if (dr.Read())
            {
                db.RegisterEmbeddedFunction("DealerID", dr.GetValue(0).ToString());
                db.RegisterEmbeddedFunction("DealershipID", dr.GetValue(1).ToString());
                db.RegisterEmbeddedFunction("DealershipName", dr.GetValue(2).ToString());
            }
            dr.Close();
        }                
    }
You can then use these functions as a Field.DefaultValue" by adding '!fn' to the beginning of the function name. For example: !fnDealerID(). To use an embedded function in a SQL filter you can specify that the result be quoted for use in an ANSI SQL statement by appending a '$' sign to the name of the function: dealer_id = !fnDealerID$().
See Also