Forms Data Controls :: Dropdownlist That Maps From A SQL Foreign Key, Which Can Be NULL?
Jan 12, 2011
This must be a common problem but I haven't been able to find an answer.I have dropdownlist that maps from a SQL foreign key, which can be NULL. Currently, I've added a "Please select..." to the top of my dropdown list and assigned it a value of 0.I know how to map from the drop down list to SQL using a CASE statement in my UpdateCommand.But how to I map from the SELECT statement to my dropdownlist? If this foreign key contains null I get "Item not in Dropdown list". I'd like to show "Please Select..." as the dropdownlist item if the SQL item contains NULL. I saw something online that says to use the value '''' for 'Please select...', but I don't think it's right, plus it doesn't work.Do I have to do something in my SELECT statement or do I have to do something on DDL.Databind?
I have a stored procedure to insert data into Table B, but when I tried to insert a null value into column ID of table B, this error came up:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tableB_tableA". The conflict occurred in database "database name", table "table A", column 'ID'.
I am guessing adding nothing to the null value column is the problem, but i don't know how to fix it... The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tableB_tableA". The conflict occurred in database "database name", table "table A", column 'ID'.
I am trying to create a stored procedure where I can insert null values in columns that have a foreign key constraint and allow nulls. The columns I am trying to insert nulls into are commentid and imageid. I have created an Insert statement in a stored procedure and I get the foreign key constraint error. Can you tell me how to allow inserting data in the other columns without having to insert anything in the commendid and the imageid?
Here is my exec of the stored procedure that is not working:
here is my latest bit of insanity. I'm using a formview control. In the insert template, I'm grabbing applicable values from my AD to populate a dropdown list. I select the user I want to insert, enter the other pieces of info required for my request and click Insert. The query responds back stating that the userid is NULL. So the big question in my mind is how can I bind userid to the dropdownlist if I'm populating that from the code behind? Here's my code behind code for that list:
I have a formview on a web page, set to insert mode as default. The form view is bound to a SQLDatasource. This datasource has a custom query written to select the details for this formview. The query joins two tables to provide relevant detail and not just an ID for one of the elements on the form view.
The first tabe contains information regarding projects and the second table contains detail regarding Resources. First table has the following definition:
I'm using Asp.Net's Dynamic Data Website project type.I've created a db that has one to onerelationship between two tables specified using a foreign key, (this could be one to many but I've used the linq designer to change it to a one to one relationship).i.e. I have a table Invoice and table CreditNote that takes an Invoice_Id as a foreign keyI was hoping that when I navigated to CreditNotes/Insert.aspx that it would display the a list of InvoiceIds in a dropdown list. It almost does this - it creates dropdownlist but only populates option value and not the text so I get something like this in the html source (notice only the value is populated - which looks empty to the user):
like to display infowindow as it is in google maps on selection of Dropdownlist with data dynamically binded using VB.net can anybody provide me the code.
I have two table BuildGroup and table DocumentTemplate. DocumentTemplate table has BuildGroupId as foreign key which is nullable. In a certain senario I update BuildGroupId in DocumentTemplate table.
[Code].....
In another senario I need to set BuildGroupId in DocumentTemplate table again to dbnull.value. I tried with different cases as in else block. It giving the error : Cannot implicitly convert type 'System.DBNull' to 'int'. How can I update a foreign key value with NULL?
I have a DetailsView on the page and I have made one of the fields a TemplateField. In the EditItemTemplate and InsertItemTemplate I have a DropdownList that is databound to a table in my Sql Server database. I wanted to add an initial value to the DropdownList namely "- select -" .
I set the AppendDataBoundItems property to true and added the initial value as a ListItem.Markup of the DropdownList
This works fine for new input. The problem is however that the database already has records that were entered through a Windows Application and many of these records has a null value in this field and exceptions are thrown when I tried to open these records and the system tried to set the SelectedValue of the DropdownList.After some more searching I found this help
This now solved the problem of opening a record where the value is null in the database, BUT now the RequiredFieldValidator is not validating anymore to make sure that a databound item is selected for this field and not the initial value "- select -". So basically now it is not checking anymore to see if valid input has been entered for the DropDownList and it accepts "- select -" thus it acts as if the field is not a required field anymore.
In short what is required is that I want to make sure that the user enters a valid selection in the DropDownList, but it must also cater for old records that do not have this field entered yet so that those old records can be opened in the DetailsView .Opening Old records (with null in that field):When these old records are opened in the DetailsView the DropDownlist should show "- select -" when the value in the database is null.
Saving records (old or new records):When saving the record in Insert mode or Update mode the RequiredFieldValidator should show that a valid input is not selected if the DropDownList is still on "- select -".
DDL3.Items.Insert(0, new ListItem(" please select ", "0"));
I have button in my page that when user click on it insert data into database
Here when users didn't select Item from dropdownlist it insert "please select" ( text that I define for DDL ) into database but I want when users didn't select Item from database it insert NULL in database....
I would like to know if the forieng key should be nullable or not. We shuld struggle for not making it nullable as much as possible or it doenst matter.
URL.... When I wrote this code in other page with different SP It didn't worked correctly I change SP in new SP I used INSERT code instead of UPDATE now when users didn't select Item from ddl3 it insert 'please select' in table these are my code
This is my UserRoleList.aspx.cs Code where i am passing the session variable to the page Default.aspx.cs..
And the error is: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. I have gone through many pages , and tried by making the AllowDbNull property making True and then different things.
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Data;
[code]...
This is the code of the second page Default.aspx.cs where i have to user the session varaible to pass in the SQL fucntion named GetDataByUserId as shown below:
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;
In the detailsview, I set a edit item template (a bounded dropdownlist control). But in database there are some data not set to a value (null). After clicking edit button in detailsview control I get the error about the value problem (Because after populating the dropdownlist, there is no item as null in it. )How to set dropdownlist selected index when the data is "null"?
I have setup my business object to have a create_date and edit_date members both datetime datatypes. My company want to display the create_date and edit_date fields in a gridview for each transaction. The problem i have is that after insterting a record it will have a valid create_date but no edit_date and when displayed in the gridview it defaults to datetime.minvalue (My default). How on earth do i show an empty field in my gridview for a null datetime field in the database?
I am using similar architecture to the Imar Spaanjaars example of a tiered solution. With a few small tweeks it has worked well for me for ages. I am passing a List<Database> to my object datasource which connects to my gridview.
In my web page displaying the list of products with address (store location) and hyper link say 'map' in gridview. Beside gridview there is one google map embedded in div. when ever user clicks on 'map' hyper link in girdview the corresponding location should show in popup in google maps. In my database i have only complete address for the each products.
I am attempting to create an ASP.NET website that incorporates Google Maps to geocode the location of bus stops that the user selects from a gridview that is bound to a SQL database. Any ideas on how to use a buttonfield to pass the address (text) for a given row to a command that will geocode that address and place a marker on the map?
Has anyone used a control that would allow them to select and bind to another data control with a foreign key? I have a grid that I can filter with a datalist and listview, but, I have a many to many relationship in the table I want to use in a control to further filter the grid that only has a foreign key to the table data in the filtered grid.
I wanted to list the bonuses in a gridview, so i made a query to return list of bonus records and my data access object returns the result set as Bonus business object ( generic collections of bonus BO ). i have bind my gridview with the bonus collection.
now my problem is that collection has the property "EmployeeID" and it will be displayed but instead of showing EmployeeID, i wanted to show Employee Name in that grid. I have a gridview where i want to list the bonus records ( bonus ID, bonus date, bonus description, employee ID) ,
i want to display name of related table in my gridView insetad of it's id. one solution is using sqlDataSource or objectDataSource, but i don't want using this appproach. i want to do this without setting any dataSourceID or join tables, in other word, i want to do this like windows form datagridViewComboBoxColumn.
I have dropdownlist that maps from a SQL foreign key, which can be NULL.
Currently, I've added a "Please select..." to the top of my dropdown list and assigned it a value of 0.
I know how to map from the drop down list to SQL using a CASE statement in my UpdateCommand.
But how to I map from the SELECT statement to my dropdownlist? If this foreign key contains null I get "Item not in Dropdown list". I'd like to show "Please Select..." as the dropdownlist item if the SQL item contains NULL. I saw something online that says to use the value '''' for 'Please select...', but I don't think it's right, plus it doesn't work.
Do I have to do something in my SELECT statement or do I have to do something on DDL.Databind?
I have a search button ..The result will be displayed in grid view if the button is pressed .. i am able to do it
But now i want to do like this ..that is my grid view is only displaying the ResultId .. I want to display the ResultName rather than resultID in the table
