I am a c#/asp.net developer and I am having to work on a VB/asp.net. I started out with VB.NET but after years away from it I'm getting confused with the syntax.
I have two variables
Dim originalDate as DateTime?
Dim newDate as DateTime?
Both nullable datetimes, originalDate is a nullable date I am getting from the database and newDate time is set in code, I need to compare them, they can either both have dates, neither have dates or one have and one not.
I have a bit of code as follows:
if origEndDate = origEndDate then
When both origEndDate and origEndDate are "nothing" this statement is false (well when I run it in the watch window it comes back as nothing)!
I don't understand why this is the case because I was under the impression doing an "=" compares the two values and as they are the same surely it should be true?
What syntax should I be using as in C# I can do the above as so:
I have a textbox that I use to gather a date. I would like to have the database store a null if this field is left blank by the user when submitting. I am using the following on my aspx page:
Every single parameter is bound just fine except toDate which turns out to be always null. When inspecting the Request.QueryString["toDate"] it retrives the right value which is 30/09/2010. It seems that DateTime expects another format when binding. What is the right format?
Got a nullable datetime member on my viewmodel.the moment it hit my controller action, the viewmodel's modelstate allready are invalid (because the member is null).Forgot...how that works? (using MVC2)Basically my viewmodel have a social security number, passport number and passport expiracy date.If the ssn is entered, I want to ignore the two passport related fields, so I made the expiracy date member nullable.
Like all other viewmodels in this app, each model have it's own validation function that will do validation, and in there I add an error that the date is required or not valid (if using passport number). mvc itself should not care about the date at all.I dont want to give the date a default value, because then the date will show when the form loads, and it must be an empty field (unless I already got a date of course.
Is there a way to use the OrderBy command in Linq with a DateTime field using the Date portion only (without the Time Stamp portion) that is nullable such as in the following query?
var query1 = from myTable in MyTable where myTable.EnteredDate != null group myTable by myTable.EnteredDate into myOutput[code]....
Since myTable.EnteredDate is a DateTime field that can contain nulls, it does not support the .Date conversion call such as myTable.EnteredDate.Date
Is there a way to convert the myTable.EnteredDate field into a date only string in the group by portion?
I am having a problem with the Client Validation not firing when I have marked a nullable DateTime field as [Required] and the value of the field is null. (It is actually stopping ALL client validation on the page working - not just the DateTime field).
Interestingly enough, once a post back has been done and the error picked up on the server, the client validation starts working.
Also if you set the date to a none null value (see commented out line in the controller) it will also work
I have replicated this behaviour in a small test project (this is deliberately very Noddy - just enough to replicate the problem)
Am I doing something fundamentally wrong or am I looking at coding some sort of work around here? (I realise that a Required nullable field sounds like a bit of a oxymoron, but I wanted to present the user with a blank field which they must then fill, not one pre-populated with an arbitrary date value)
Am I going to be able to query (using LINQ to SQL) a database field with a type like the following "public System.Nullable<System.DateTime> Spouse_DOB"?
I'm trying to use the following code: [Code]....
and I get the error "'System.Nullable<System.DateTime>' does not contain a definition for 'Month' and no extension method 'Month' accepting a first argument of type 'System.Nullable<System.DateTime>' could be found (are you missing a using directive or an assembly reference?)"
Is it because this DateTime column allows a NULL value (since everyone isn't married in my database)?
Error 1 'System.Nullable<System.DateTime>' does not contain a definition for 'Month' and no extension method 'Month' accepting a first argument of type 'System.Nullable<System.DateTime>' could be found (are you missing a using directive or an assembly reference?) C:Working WebsitesGrannys Clan Address BookDefault.aspx.cs 38 26 C:Working WebsitesGrannys Clan Addres
I created a UserControl and added a public DateTime property. I want to set this property in Markup (ie. <cc1:MyControl runat="server" id="MyControl1" DateTimeProp="1/1/2010" /> ) however I live in a place with a dd/mm/yyyy date format so it complains if I set something like "20/1/2010". Is there a way to set markup in my local datetime format or do I have to conform to "mm/dd/yyyy"?
I am trying to store a SQL Server datetime into MySQL datetime field, but MySQL stores the date value as all zeros. I use this function to trim the fractional part from the SQL Server datetime, but get the same result when trying to store it in MySQL.
I have a ASP.NET MVC view that displays a single ServiceProvider object. In this view there is a selectlist that lists one or more ServiceProviderGroup objects and uses the Id property for the value and the Name property for the text. In this list I also show a entry with a value of -1 and text of "No Provider". When the Edit[Post] method is called the Id value from the select list maps to a nullable property (GroupId) on a ServiceProvider object. When a value other the -1 is selected from the list it works as expected. But, when the value is -1, I want a NULL reference to be applied to the GroupId property during the UpdateModel call. Within the Edit method, prior to calling UpdateModel, I have tried replacing the entry within the Controller.ValueProvider with a null reference and adding a ValueProviderResult which contains a null reference, but the UpdateModel always has an issue (InvalidOperationException).
Basically I want to get a null value displayed as blank "" in the TextBox, and a number as a number. If the TextBox is blank MyProperty shall be set to null. If the TextBox has a number in it, MyProperty should be set to this number.If I try it I get an exception: "Blank is not a valid Int32".
But how can I do that? How to work with nullable properties and Bind?
I have a problem with passing a model to a controllerIn my controller I have a HttpPost function that gets a EF model.The problem is that the form does not contains all properties of the EF model.When the function is called that gets this EF model, I get error messge of fields that are not nullable in the EF model.That's because the fields are not in the form, so the not nullable properties gets no value.
I have a small Linq to Sql database application, with a table set up with a datetime field (allow Null). I am able to submit 'Nothing' into the datetime field after setting my .dbml table | field | property to AutoGenerated = True. Why this is I don't know, but it works. Now that I can submit an empty datetime field to the database, I am having trouble loading it into an object with a property set as datetime.
Example: of property in object
Private _deliveryDate As DateTime = Nothing
Public Property DeliveryDate() As DateTime [code]...
Example: setting value when instanciating the obect
dim test as new dateObject(Nothing, ...) ' where (Nothing) represents the datetime field retrieved from the database set to null.When I try the above line I get "Nullable object must have a value."
I get this error "Type 'String' must be a value type or a type argument constrained to 'Structure' in order to be used with 'Nullable' or nullable modifier '?'." [:(]
Function Index(ByVal product As Product, ByVal category_1 As Nullable(Of String), ByVal category_2 As Nullable(Of String)) As ActionResult ... End Function
This is actually a situation where LINQ as follow:
Code: Dim query = From loadedfile In dtloadedfile.AsEnumerable() _ Join householdPanels In dtHouseholdPanels.AsEnumerable() _ On CType(loadedfile("Household_number"), Integer) Equals _ [code]...
when i get to col.DataType = t.PropertyType, i hit an error where it says Nullable datatype is not allowed. I know the t.propertytype returns nullable as datatype, however, this nullable type do have a normal datatype declared too. ie Of System.Nullable(Of Integer) from the LINQ query. But how do i get that information?
ps: this function is taken somewhere from the web, so you might recognise it.
I remember being told that you can add some syntax to the end of a statement that will do something if the field is null. Pretty vague, but I cant seem to find anything about it via google.
I definitely isnt how to set a field to be nullable. I know that.
Here is an example of what I want.
int? field1 = 0;
field1 = int.parse(string2); (where string2 is a passed value, that could be null)
I thought there was something you could put at ?? if it is a null, such as:
field1 = int.parse(string2) ??;
Or do I have to check every if every string2 is null before making that statement.
Can anyone reliably get the EDS to save a nullable column to the databse as a "null" when bound to any of the controls such as "FormView"?I have tried using several different UpdateParameters (Session, ControlParamater, Parameter, etc). I have tried setting "ConvertEmptyStringToNull" to true and leaving the property off entirely. Nothing works. On my "Inserts" it works fine.(I have made sure the column is set to nullable = true in the Entity Designer.....)
