Can Check Rows Returned In A QueryString Parameter Based Entity Framework Query
May 29, 2010
I need to check if any rows are returned in a QueryString here's what I have so far.not sure what code to put to see if the row count is greater than 1
private void BindDataToGrid()
{
//MessageBoardEntities3 is ThemeableAttribute connection string name
int TID = Convert.ToInt32(Request.QueryString["ThreadID"].ToString()); // if Post ID is int
var context = new MessageBoardEntities3();
gvPosts.DataSource = from p in context.Posts
where p.ThreadID == TID
select new { p.Post1, p.PostID };
gvPosts.DataBind();
lblNoPosts.Text = "No posts found for this thread.";
}
How to make this method return boolean value, depending on query return. False - nothing, True - data exists. Before i just returned int from uniqueQuote.Count() but does not look like great method.
Users Id Username Email Password UserStatuses Id Name Users_UserStatus Id User (FK - Users: Id) Status (FK - UserStatuses: Id) StatusDate
As you can see, UserStatuses is a reference table with various statuses. Users_UserStatus is a join table between Users and UserStatuses. Using Entity Framework, how can I do a conditional to check if the latest StatusDate is "Pending"? As of now, I have the following:
I have a web form (Page1.aspx) in which I am passing an ID as query string to another page (Page2.aspx). Now in this page I have EntityDataSource which binds to GridView. How should I populate this gridview with that ID?
Eg. If my ID is 1056, then in my DataGridView in Page2.aspx should populate elements of this ID.
This is the code:
protected void Page_Load(object sender, EventArgs e) { string getEntity = Request.QueryString["EntityID"]; int getIntEntity = Int32.Parse(getEntity); if (getIntEntity != 0) { //What should I do here??? } }
Trying to get the number of rows returned in a query in Visual Basic.The query returns 3 rows.Dim td As Integer = dataset1.Tables(0).Rows(0).ItemArray(0) has a value of 1.Dim tg As Integer = GridView1.DataSource.tables(0).rows.count has a value of 3.1. Why do aren't they both 3 ?2. Is there a best way of getting the number of rows ?3. Where can I find a tutorial or book that explains the notation above ?
string strConString = ConfigurationSettings.AppSettings[ "conString" ]; myConnection = new OdbcConnection(strConString); myConnection.Open(); // open connection string strSelect= "select * from tbl_howells_product_data where title like" + "'" + strsearch + "%" +"'" + "order by product_id asc"; OdbcCommand myCommand = new OdbcCommand(strSelect, myConnection); dtrReader=myCommand.ExecuteReader();
The problem is I need to check to see if any data has been returned from the SQL query, if there are no rows/ data returned by the query then I need to display a message to say that there aren't. I know that there isn't a 'number of rows method' for the dtrReader, so does anybody know how I could do this?
Using C#, how can I check the total number of rows returned from a database when using a Repeater? The reason I need to check is I need to alter the presentation of the data when there is only 1 row returned.
I'm new to ASP.NET MVC and I'm trying to implement an address manager.I'm using Linq2Entity Framework. I've got a table with contacts and one with phone numbers. These two tables are linked by a contact_has_phone_number table. The Entity Framework enables me to get all phone numbers that are assigned to one contact. This is done by calling contact.PhoneNumbers which returns a collection of phone numbers.
There are some tutorials explaining how to create a Model based on Linq to Sql or The Ms Entity Framework. Can I use my custom code for a model? If we have the controller with the code :
[Code]....
This returns a List<Movie> to the view that knows what to do with it. Is it possible that I create a method called MovieSet that returns a List<Movie> using a sql qry or a stored procedure call without the creation of an Object for this purpose ? Or do I need a Movie object? Lets say that I just to do my query, loading data into a dataTable and load that data to a list of movie objects. Because the code created by the Entity Framerwork is too big for a quick reading.
In my asp.net+vb web with access database there is a page which displays data as per query string and the string is PNO and all data is correctly displayed in gridview and dataview. there is a Image1.ImageUrl and i used the following code but it is not working
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Dim PNO As String PNO = Request.QueryString("PNO") Image1.ImageUrl = "C:/wing/Photos/" + PNO + ".jpg" End Sub
i'm trying to use Entity Framework to insert into SQL SERVER 2005, using Visual studio 2008.the following codes are a Button onclick event,I want to insert into DB multiple rows at a time
[Code]....
however this does not work, it seems we can only insert into DB only one row at a time
i'm trying to use Entity Framework to insert into SQL SERVER 2005, using Visual studio 2008.the following codes are a Button onclick event,I want to insert into DB multiple rows at a time
[Code]....
however this does not work, it seems we can only insert into DB only one row at a time
Best way to show the SQL trace of a LINQ query to Entity Framework 3.5? I am using ASP.net and EF 3.5.
Dim dbo As Web.Portal.RBMEntities = New Web.Portal.RBMEntities Dim Query = From RoleAllocations In dbo.RoleAllocations Where RoleAllocations.user_id = _ID And RoleAllocations.expire_date > Today Select RoleAllocations
I have a web app for our golf club. When I compute handicap index for each golfer, I have to select the most recent scores and then a subset of those scores depending on how many rounds of golf the golfer has played. All the scores are entered into a single SQL Express table called "Rounds". Verbally, this is what I'm trying to do:
1) select the twenty most recent golf scores (sort on date descending, "take(20)") [if less than 20 records, then select all available];
2) for this set of records, select the 10 lowest scores (or smaller number if golfer has less than 20 rounds);
3) compute the average round differential for the subset of records, etc. to calculate handicap index (this step is working ok...)
My current VB code has this LINQ query (which is flawed -- it selects the lowest handicap differential scores of ALL records for the filtered user):
[Code]....
How do I modify this query to accomplish items 1) & 2) above? It seems this should be simple, but my experience with queries is still limited.
I need to set up the slide show based on a querystring parameter. I thought I had this figured out, but I clearly don't understand something about how the webservice works. I have this in the .aspx page:
In an MVC view, I'm looking for a way to determine if a parent entity's collection of child entities is empty, so I can decide if I need to call a RenderPartial() or not.
For a one-to-one I've been using the following:
<% if (Model.Book.GenreReference.EntityKey != null) %> {.....}
but I'm unsure how to do it in a one-to-many scenario, or if it can even be done without the use of Include() or Load().
public class Category { public int CategoryId { get; set; } public string Name { get; set; } } public partial class CategoryMap : EntityTypeConfiguration<Category> { public CategoryMap() { this.HasKey(c => c.CategoryId); this.Property(c => c.Name).IsRequired().HasMaxLength(400); } } public class MyObjectContext : DbContext { public MyObjectContext(string connectionStringName) : base(connectionStringName) { } public DbSet<Category> Categories { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Configurations.Add(new CategoryMap()); base.OnModelCreating(modelBuilder); } }
Now when I run the following code I get an exception (GenericArguments[0], 'System.Int32', on 'System.Data.Entity.Internal.Linq.ReplacementDbQueryWrapper`1[TEntity]' violates the constraint of type 'TEntity')
DbDatabase.SetInitializer<MyObjectContext>(new DropCreateDatabaseIfModelChanges<MyObjectContext>()); using (var context = new MyObjectContext("NopSqlConnection")) { var query1 = from c in context.Categories select c.CategoryId; var test1 = query1.ToList(); //works fine var query2 = from c in context.Categories where query1.Contains(c.CategoryId) orderby c.Name descending select c; var test2 = query2.ToList(); //throws the exception }
I am new to this, and I am trying to implement a linq query similar to db.Genres.Include("Albums") command from
mvc music store using my current DB setup. I realize that the tutorial mentions Checlking the "Include foreign key columns in the method" when creating the tables in ADO.NET, but if I am using LINQ to SQL classes, then how can I obtain the same effect. And how do I use db.Genres.Include("Albums") to simplify my life?
I just tring to a complex (for me) with ado.net entity framework this is the structure: In practice it is a sort of group purchasing (Buyers) For each group of purchase (Buyer) should have the opportunity 'to select all products of the brands indicated in buyer I'm doing function to return correct data like this:
public List<Product> GetProductsByBuyer(int vBuyerId) { Buyersctx.Products.MergeOption = MergeOption.NoTracking; return (from lProduct in Buyersctx.Products.Include("Brand").Include("Buyers") where select lProduct).ToList(); }
I'm currently learning entity framework (from the Julia Lerman book "Programming Entity Framework") and got really confused at the grouping part.
var contacts = from c in context.Contacts group c by c.Title into myGroup select myGroup;
This is supposed to return a Grouping<K,T> type, but the book didn't give an example on how exactly do I access this "contacts" query and I can't figure it out. When I did foreach(var contact in contacts), my "contact' variable has no knowledge of any of the properties of the Contact type (contact.FirstName etc).
