C# - Bind The Values Without Duplicates From Database Into Dropdown Using LINQ?
Apr 2, 2011
I have a small issue binding the values into a dropdown using LINQ in ASP.NET code-behind.
var clientquer = from i in Entity.New_Bank select i;
//var q = (from s in names
// select s).Distinct();
// var getlendername = (from db in mortgageentity.New_Lender group db by db.Bank_Name into t select t.Key).ToList();
if (clientquer.Count() > 0)
{
ddlbankname.DataSource = clientquer.ToList();
ddlbankname.DataValueField = "Bank_ID2";
ddlbankname.DataTextField = "Bank_Name";
ddlbankname.DataBind();
}
It is binding with duplicate values, but I don't want bind duplicate values. I'm trying to solve this by using a group by clause, but it is not working.
I would like someone to explain how I can pass a drop down list from the presentation layer to the controller using the Model View Controller Design Pattern from Microsoft in order to bind enum values to it?
I want to use this to insert and edit values from a db. For example when adding a record the user selects 'One Day Shoots' and 1 gets inserted into the database. Then if the user goes to edit the page since the value in the db is 1 then the 'One Day Shoots' is selected.
One way I considered accomplishing this was by using a hidden feild - when the user selects something in the dropdown list the field is updated with the value, then when the user actually adds the record the value in the feild is submitted. I'm pretty sure this would work but is there a better way?
I am trying to bind a record to a textbox using a Dropdown selected index change. I get the error.
Conversion failed when converting the nvarchar value 'DrFirstName DrLastName,Ph.D.' to data type int. is it because I concatenate the name and prefix of the DR into the Dropdown list like this,
Code: SELECT ID,EmailAddress, DrName + ',' + PreFix AS DrName FROM DrNames
Here is the dropdownlist code that I want to populate the textbox with the emailaddress in the table associated with Dr name and ID.
Code: Private Sub DropDownList1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles DropDownList1.SelectedIndexChanged Dim dt As New DataTable() If DropDownList1.SelectedItem.Text = "OTHER,..." Then txtRx1.Visible = True DropDownList1.Visible = False End If
I have query that returns a line that looks like this belowA NEWYORK PROGRAM AA NEWYORK PROGRAM Bnow, the NEWYORK is inputted into a dropdownlist and the program A and program B is inputted into a dropdownlist as wellI am using utility.ControlTools.SetListControl for my dropdownlist. I would like a situation where my dropdownlist only contains one NEWYORK instead of two and my dropdownlist for programs to contain Program A and program B. Can this be done.
I have created an asp.net customizable gridview where user will be able to add and delete data. Now I face some proplem with this gridview. now I want to add a dropdown list (which is dynamically bind with database) inside the grid. I created code and it bind well. when the page is post back previous selected dropdown list value lose and set to selectedIndex=0; For this reason I used if(!page.Ispostback) and put the dropdown binding code inside this. Here I faced a problem. The problem is when I want to add data inside grid the dropdownlist missin bind. How can I overcome this problem? For your kind observation I given entire code below:
how to bind values in combobox from database in that combobox my first value should be display as <----select----->, but i have no such values in my database.
how to bind database values to a calendar. What i am trying to do is the following. i've got a stored procedure in an sql server database which checks if a backup is done correctly or not with some other information in different collumns. There is one column with the end date and one column with the status of the backup.
what i am trying to do is to bind the calendar so that when the backup finished on lets say 27 th of march and it ended correctly or not i want to see in my calendar on the 27th of march the status information. how is the best way to approach this.
I have a ASP:DropDown list which is populated by the following:
public void Fill1() { string connectionString = WebConfigurationManager.ConnectionStrings["CRM2Sage"].ConnectionString; using (SqlConnection _con = new SqlConnection(connectionString)) using (SqlCommand cmd = new SqlCommand("SELECT * FROM Products", _con)) {
I'm stuck with a problem to populate a DropDownList control with values from the database using item field template in read only mode. since I'm new to ASP.NET. Below is the code and the error I'm getting:
'PictureReadOnlyCategories' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentOutOfRangeException: 'PictureReadOnlyCategories' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value
The code for this is :
<asp:SqlDataSource ID="categoriesDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand ="SELECT [CategoryID], [Name] FROM [Categories] WHERE ([UserId] = @UserId)"> <SelectParameters>
i am using a list view to view, insert, update and delete my data for the admin page this admin page made for the news and we have categories for that so i need to use a drop down list for these categories and when the admin choose on of these categories records its value as an ID to the database.
<asp:QueryStringParameter Name="CategoryID" QueryStringField="ID" /> </SelectParameters> and ([UserId] = @UserId), the dropdown list control will populate values from the database but when i live those 2, it won't populate any value from the database. When i remove the <asp:QueryStringParameter Name="CategoryID" QueryStringField="ID" /> </SelectParameters>,and live ([UserId] = @UserId), i get the error : Must declare the scalar variable "@UserId".
How can i load the QuoteNumber database column values into dropdown list which is autogenerated column.I am able to generate the QuoteNumber value and same inserting into database simultaniously all the Quotenumber values should load into dropdown, these two should happen in one click button event.My QuoteNumber dropdown name is "DDQuote" Code for generating Quotenumer and same inserting into database.
Protected Sub btnAQ_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAQ.Click Console.WriteLine(updateRecord("insert into quotes (PartNumber) values ('" + txtPart.Text + "')")) retriveDataToDataGrid() End Sub Function updateRecord(ByVal query As String) As Integer Try Dim connectionString As String = "Database=fabdb;" & "Data Source=localhost;" & "User Id=root;Password=pacvision" Dim rowsEffected As Integer = 0 Dim connection As New MySqlConnection(connectionString) Dim cmd As New MySqlCommand(query, connection) connection.Open() rowsEffected = cmd.ExecuteNonQuery() connection.Close() Return rowsEffected Catch ex As Exception Console.WriteLine(ex.Message) End Try End Function
Ive been strugglng with this one problem for a while now. I have an application as: SelectCommand="SELECT [CategoryID], [Name], [UserId] FROM [Categories] WHERE ([UserId] = @UserId) ORDER BY [Name]"> <SelectParameters> <asp:QueryStringParameter Name="CategoryID" QueryStringField="ID" /> </SelectParameters> [code]....
the dropdown list control will populate values from the database but when i live those 2, it won't populate any value from the database. When i remove only the <asp:QueryStringParameter Name="CategoryID" QueryStringField="ID" /> </SelectParameters> and live ([UserId] = @UserId), i get the error : Must declare the scalar variable "@UserId".
I have Dropdown for Quotenumber(auto increment ).i have created a function to retreive the data from database.data loading into dropdown. when i click on Addquotenumer button the new quotenumber generated and same loading into dropdown but 2 set of Quotenumbers are displaying rather than singleset, i debudded the code the reason was i have called this function twice one is form load and another one in AddQuotenumber button event,both should manadetory as per my requirement. how can un load this dropdown before AddQuotenumber button
Function to retreive data to dropdown Public Sub retriveDataToDropDown() Try Dim connectionString As String = "Database=fabdb;" & "Data Source=localhost;" & "User Id=root;Password=pacvision" Dim query As String = "SELECT QuoteNumber FROM quotes" Dim connection As New MySqlConnection(connectionString) Dim da As New MySqlDataAdapter(query, connection) Dim ds As New DataSet() If da.Fill(ds) Then DDQuote.DataSource = ds.Tables(0) DDQuote.DataTextField = "QuoteNumber" DDQuote.DataBind() 'DDQuote.Items.Insert(0, New ListItem("Select", "Default value")) End If connection.Close() Catch ex As Exception 'Console.WriteLine(ex.Message) End Try End Sub AddquoteNumber button code Protected Sub btnAQ_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAQ.Click Dim connectionString As String = "Database=fabdb;" & "Data Source=localhost;" & "User Id=root;Password=pacvision" Dim rowsEffected As Integer = 0 Dim Query As String = "" Dim connection As New MySqlConnection(connectionString) 'Dim cmd As New MySqlCommand(Query, connection) connection.Open() Query = "insert into Quotes(query follows...................) retriveDataToDropDown() retriveDataToDataGrid() connection.Close() End Sub
I am struggling to create a webservice method using LINQ technology and to populate a dropdown in a form. Here is the Webservice code.
[WebMethod]
public string[] GetAllCountries() { LinqClassesDataContext db = new LinqClassesDataContext(); var q = from c in db.ListContinents()select c; return q.ToList() ; }
And here is the form code behind
protectedvoid Page_Load(object sender, EventArgs e) { WSClass WS = new WSClass();//bool ds = WS.GetAllCountries(); var v = WS.GetAllCountries(); ddlContinent.DataSource = v; ddlContinent.DataBind(); }
I Have the gridview control with 2 dropdown list and 2 text boxes,When the textbox chnaged event happen 1 row will create and the dropdown back to initial values( its not retaining the selected values),I am binding the control after text changed method,Is there any properties needs to be set or any other way we can retain the values in postbacks?
in a web form, i am having two drop down controls, and in the first one control i am having, state names like some thing, and in another i have to fetch the concurrent city names for the first control, like if i select city name as 'A' it must fetch the related city names for the 'A' how could i do this.
Prior to using a ViewModel, I could easily pass the "soon to be edited" object directly to the view without needing to fuss over setting individual properties etc as the View conveniently accepted the Employee type directly..
[HttpGet] public ActionResult EditEmployee(int? id) { EmployeeRepository ER = new EmployeeRepository(); Employee SomeEmployee = ER.GetEmployee(id.Value); if(SomeEmployee!=null) return View(SomeEmployee);
But now I'm using a ViewModel with DataAnnotations attributes applied over the top of various properties for validation purposes. Which creates a problem.. After fetching the "soon to be edited" object from the db, setting the ViewModel's values is suddenly a whole lot more complicated. I can't simply pass the retrieved object straight to the view, as the View now expects the VMEmployee type instead. I would like to be able to do something like:
[HttpGet] public ActionResult EditEmployee(int? id) { EmployeeRepository ER = new EmployeeRepository(); Employee SomeEmployee = ER.GetEmployee(id.Value); if(SomeEmployee!=null) return View(new VMEmployee(SomeEmployee));
All paths seem to lead to a huge constructor which manually sets the values of each individual property. But I never had to do that before when I wasn't using a ViewModel. Model binding was a blessing! My objects also have complex child objects, which my form is also collecting values for, so this would be a huge/verbose task against DRY principals. I don't even really want to use a ViewModel, but am forced to because I need two different DataAnnotations rule sets for different validation scenarios applied to the same object.
All I want to do is be able to have two different DataAnnotations rule sets for different scenarios. I.e. public-facing www site vs internal-facing admin site. DataAnnotations doesn't seem to be flexible enough to easily cater for this common need. I've tried AutoMapper, but it throws an error saying it can't map my object types, I suspect because Employee was auto-generated by LINQ to SQL. What is the most elegant way to achieve this while sticking to DRY principals?
