DataSource Controls :: Insert Dbnull With Linq To SQL?
Apr 28, 2010
I am trying to do an update and if no selection has been made in a dropdownlist (integer) or date field I would like to insert a dbnull value. But I am new to Linq to Sql and wonder if this is possible and if so how to process. I have the following code but the DBNull.Value is giving me an error.
Dim context As New SondageDataContext()
Dim repondant = (From r In context.Repondants Where r.RefRepondant = iRefRepondant Select r).Single
repondant.Prenom = strPrenom
repondant.Nom = strNom
'dates
If dtAdhesion > Date.MinValue Then
repondant.DateAdhesion = dtAdhesion
else
repondant.DateAdhesion = DBNull.Value
End If
'Integer for dropdownmenu
If iOccupation <> -1 Then
repondant.RefOccupation = iOccupation
Else
repondant.RefOccupation = DBNull.Value
End If
context.SubmitChanges()
My database includes a table with sever filds which are defined as (varchar(1),null), I tried using DBNull.Value, null, ' ' but cannot get a null inserted in that field of the database,
I use the following code to insert recode to a sql 2008 table, the field ID of DBProgram is IDENTITY, so SQL 2008 SERVER will pass a value to it automatically. How can I get the ID value of the record I just insert ?
DBProgram dbProgram = new DBProgram(); db.DBPrograms.InsertOnSubmit(dbProgram); db.SubmitChanges();
I tried to find a LINQ section on this forum, but couldn't, so I'll post this here since is deals with LINQ, C#, MVC, SQL Server, and well...just about everything.
Here's the details....My Application is an ASP .Net MVC 1.0 app, using C# 3.5, SQL Server 2005 Std, and LINQ to Entity.
In my View, I have numerous Html.CheckBox controls, they get passed to my Controller as a string collection via a JQuery Ajax call. The values of each checkbox are seperated by a comma(,). I then Split the string, to get the individual values. The overall purpose to to allow users to build a custom report with only the data elements they have checked the boxes for. Here is my controller:
[Code]....
The part that I am having a problem with is that I only want to Insert the data elements into my DB table for the ones that the user has selected the checkbox for. So, for example, I'd like to do something like this:
[Code]....
I don't know if there is a LINQ switch statement in which I can access outside variables and the columns of the table, or any thing like that.
I am using LINQ Expression to insert records in SQL Table. My Table dosen's have any Primary Key Field. Whenever I Am trying to Insert Records in Table using LINQ Expression, this always occurs an Error that 'the Table You are using to insert Dosen't Have Any Primary Key Field.
How I Will Insert Records Without Having Primary Key ?
I'm new onto LINQ and im working on a asp.net application which uploads a requisition from a preformated text file that is coming from another application.
I have a webpage, i have a usercontrol in it , its name ispersonal1, i have tow Radiobutton in this usercontrol, the id of one of them ismale and the other one is female, it is obviously that each time we fill one of these radiobuttons and the other one will be null,in my database the type of these fields are bit , and they have allow null, i defined a property for my usercontrol like this:
I have a recordset in a gridview that comes from an outer joint that creates null values in the recordsetWhen I write to the database using stored proc defined in datasource I get dbnull error.I'm trying to process the onDeleting event in the code behind but don't know what to write or if that's the best wayI need to call a stored proc and if the last parameters value is null then the stored proc does one thing, if it's no null it does something else.However DBNull doesn't ssem to be working.
I'm new to Linq. I have searched and searched the web for a soluion, and can't find anything. I have a Linq query and I want to insert a row ("Select User") to the top before I pass it to the drop down list. I've been trying to use the Union but to now avail (it keeps telling me that my object doesn't support the Union method). My code, prior to attempting to inser a row, is very simple.
public SelectList DropDown_Users() { var context = new VivarianDataContext(); var query = from t in context.AspnetUsers select new { t.UserId, t.LastName }; list = new SelectList(query.AsEnumerable(), "UserId", "LastName"); return list; }
Now I try to insert a row and I found this on the internet and it seems to say that his solution will work. But it is filled with syntax errors. [URL]
I tried to implement it using the following code, but it doesn't compile.
public SelectList DropDown_Users() { SelectList list; //get the original data var context = new SQL2005633131VivarianDataContext(); var query = from t in context.AspnetUsers select new { t.UserId, t.LastName }; //create a dummy table with an empty row var AllUsers = new List<AspnetUsers>(); var BlankUser = new AspnetUsers() {UserId=System.Guid.Empty, LastName="Select One"}; AllUsers.Add(BlankUser); //use Union to join the data - ERRORS HERE var newTable = AllUsers.Union(query); list = new SelectList(newTable.AsEnumerable(), "UserId", "LastName"); return list; }
I get the error - Conversion from type 'DBNull' to type 'Integer' is not valid. - on the line.....
Dim newid As Integer = e.Command.Parameters("@latestRowId").Value.........in vb code behind.
I have the identical code for another page with the exception of the field names and it works fine. The only thing I did differently, as far as I know, is I copied the asp and code behind from the page that works into this page and manually changed the field and table names. I don't know what the problem is. Does anyone see any problems?
I have a 20 to 30 fields on a form. Most of them are optional. However, the users can fill out what they want. If a user dosen't fill in a field when data is sent to the database it's sent as blank, instead of NULL. Is there a way I can generically say "for all textboxes if Equals("") then DBNull.Value". Without going through each and every textbox?
I am writing a plugin to help with a current ERP system we have that I am not allowed to modify the data structure at all. The table I am dealing with has over 100 columns and I am wanting to set my linq object propertychanged event and submitchanges or do I really have list out each property and set it equal to the new one?Below is an example of what I am trying to do:
Like that I have large number of controls on my form. I have dought, if I assigned like this, db.usp_ATI_FetchPatientDetails(iPatientID).ElementAt(0).Last_Name.ToString(); to every control, then I have set of controls like,
My question is that, for each control the Stored Procedure called or not? If it is yes then it is time consuming and I need to use LINQ to DataSet or LINQ to Object rather than to call SP for each control. What is difference between LINQ to DataSet and LINQ to Object?
I am trying to pass in as an insert parameter for SQLds2 the scope_identity of the insert of SQLds1.
Exception Details: System.InvalidOperationException: Error executing 'InsertCommand' in SqlDataSource 'SqlDataSource1'. Ensure the command accepts the following parameters: @Name1, @NewId
I do have a details view, which insert data to a database table using SQL Datasource. Now i need the data to be inserted in to 2 tables instead of one.
I am using 1 textbox with a Ajax Calendar extender to allow my user's to select a date graphically (exp: 12/15/2009). I have another textbox for the hour and minutes in military time(exp: 15:30). I think i have the code to grab the data from the 2 textbox's and combine them to be inserted into the field (exp: 12/15/2009 15:30). Here is my insert code for the Field:
[Code]....
However unless I make all the fields Nullable the insert fails, on top of that none of the other field that I have selected on the Detailsview Insert or Edit are inserted into there fields. Half of my fields have to be non-null values. So how do I fix this?
I can supply additional vb code and the aspx code if needed.
This is the error I'm getting: Cannot insert the value NULL into column 'Operation_type', table '/GAOSDB.MDF.dbo.BC_Perf_Log'; column does not allow nulls. INSERT fails. The statement has been terminated.'
This is the first non-null column.
I need to get this figured out because I have 30 other web pages that will be utilizing the same approach.
Conseptually what I'm doing is simple, and technically it may even be simple, but I'm still rusty. Here's what I'm trying to do:
I have a webform that allows the user to enter a new record, and in there I have also included a couple FileUpload controls. Upon clicking the "Save" button, I'm saving the details entered into one table (ITEMS), and also inserting the FileUpload details (path, id, upload_user) into another table ATTACHMNTS). Because one ITEM can have many attachments, I needed to split the tables up. So on save, I need to save the ITEM, save the ATTACHMENT, and then also put the ITEM_ID in the ATTACHMENT table. I'm second guessing myself because I think all I'd have to do is after I do the ITEM insert, do a SELECT MAX on the ITEM table and hold the newest (MAX) id in a variable and then use it in the ATTACHMENTS update. I'm not 100% on this because there IS a chance that someone else could save a few milliseconds later and I'll link the wrong ITEM. See my delima?
I have a project that I was using Access for but now find I have to change to SQL Express. Well I have no big problem with that but I now find that the SQL Statement I have been using was for OLE and does not work in SQL/Express. I am not even sure anymore if I can dump the entire CSV file in at one time? The statement I was using is below.
[Code]....
Here is my problem. What is the INSERT statement to insert a complete flat (CSV) into SQL Express? OR what method can I use to preform this task?
I am trying to write a table output from SQL database to a gridview/ Data List through an Object Data Source. I am a new starter and your help will be useful.
public List<Staff> GetStaff() cmd.CommandType = SqlConnection con = new SqlConnection(connectionstring);SqlCommand cmd = new [code]...
i have two sqldatasource controls. one i use to display data in textbox's ,filter'd by a select parameter in page behind code. Once checked, i want to copy this data to the other datasource ,by selecting checkbox.Then display this data in detailsview control.
At present the two datasource controls declared , render data to the page simultaneously during pageload. I want to first check data in textbox's from first source, before second datasource is rendered to screen. note, both are filtered by a page variable. i wish to leave the textbox datasource control in situ, as other controls and code depend on it.The other detailsview datasource is my problem?
public IEnumerable<Customer> GetCustomers() { Table<Customer> custObject = context.Customers; IEnumerable<Customer> filteredCustList = from customer in custObject select customer; filteredCustList; } GridView2.DataSource = utilLinqClass.GetCustomers(); GridView2.DataBind();
(no errors at build time or at compile time) Error I am getting is: An attempt to attach an auto-named database for file App_Dataaspnetdb.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
