Bind null data in DropDownList

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Bind null data in DropDownList

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Vincent C.	Vincent C. posted 17 Years Ago Topic Details Share Topic
Group: Forum Members Posts: 2, Visits: 10	Hi, i'm a really Strataframe beginner (in english too) and i learn for 3 weeks on the c-sharps sample (great thanks for that !! ) my first really big problems is to have a form with data bind on a table (name: Championnat), this form contain a dropdownlist bind on a key from a child table (name: TypeChampionnat) here it is PopulationType="BusinessObject" Width="175px" BusinessObjectName="BOChampionnats" BindingField="c_TypeChamp"> displayfieldnamesalternate="Libelle\|" dropdownformatstring="" formatstring="{0}" methodtoexecute="FillTypeChampionnat;" valuemember="Code"> c_TypeChamp: the foreign key FillTypeChampionnat: the method that fill the list When i try to add() a new record in the business object it raise an exception [ArgumentOutOfRangeException: 'lstTypeChampionnat' a un SelectedValue qui n'est pas valide, car il n'existe pas dans la liste des éléments. Nom du paramètre : value] System.Web.UI.WebControls.ListControl.set_SelectedValue(String value) +1827626 i know it's "normal" because the field c_TypeChamp is null i know i can set a default value in the method "_SetDefaultValues()" BUT i don't want to set a default value so what can i do ?? a solution in asp.net forum is to populate manualy the dropdownlist with a default "-1" value with AppendDataBoundItems="True" and ListItem Selected="True" Text="" Value="-1" but it generate the error Générer (web): Vous ne pouvez pas utiliser la collection par défaut 'Items' de MicroFour.StrataFrame.UI.Web.DropDownList sans les balises de propriété lorsque vous utilisez une version filtrée de la même collection. thanks for your help and thanks to Michel Levy to introduce me to strataframe
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Vincent C.	Vincent C. posted 17 Years Ago Post Details Share Post
Group: Forum Members Posts: 2, Visits: 10	Greg McGuffey (10/03/2008) Second, setup the TopMostValue of the DropDownList to use the value that is the field's NULL value. I.e. you might set the text to "" and the value to whatever your returning for NULL, like 0. Note that the value is a String, so if you are using a null return value like Integer.MinValue, you probably want to set that in code, otherwise you'll have to type in the actual value. I hope that was helpful. If not, keep asking questions! Great thanks ! Michel Levy (10/03/2008) And if you don't want a default value to that combo, do you allow null value in the field c_TypeChamp (in BO mapper), or do you want to check for a value before saving? Where do you want to check? in the Business Layer, or in the presentation layer? uh oh wait ... step by step i learn how to put a null value in database after that i add a constraint in my SQL Serveur database ALTER TABLE [dbo].[Championnats] WITH CHECK ADD CONSTRAINT [FK_Championnats_TypeChampionnat] FOREIGN KEY([c_TypeChamp]) REFERENCES [dbo].[TypeChampionnat] ([Code]) and im going to read this article, it sounds great ! http://www.atoutfox.org/modules/articles/pdf/0000000630.pdf Michel Levy (10/03/2008) and, hem, , why do you learn SF on a web application? AFAIK, your app will be in winforms, and it will be easier (for me ) to help you on a win app. because the application i developp is not for my job, it's for me
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