VS 2010 - Selecting A Parameter From A Dropdownlist?
Aug 4, 2010
I have a drop-down list that is dynamically filled with a set of values. By viewing the source code in the browser I can tell that this list is correctly filled with the "value" and "text" parameters.
But if I try to retrieve the value using ddl.SelectedItem.Value I get the error "Object reference not set to an instance of an object" which means that there is no parameter in "value" to retrieve ...
Page_Load() contains an "If Not IsPagePostback" in which the list is filled. I don't want to use AutoPostback = True since I want to retrieve the value-parameter when I click a "save" button. I must have missed something fundamental here that I do not grasp ...
The code to fill the list looks like this:
Code:
Dim ds as Dataset ()
ds.ReadXml(the path to an xml file)
ddl.Items.Add(New ListItem("destination", "destination"))
ddl.DataSource = ds.Tables(0).DefaultView
ddl.DataBind()
This snippet does not generate any errors: Everything is printed as it should!
But inside my Submit function I cannot be retrieve the parameter:
I am trying to set the item that is selected from a drop down list based on what it in the database for that particular record. I am filling the dropdown list with a SQL DataSource I have tried a couple of example that I have found for selecting the item in the list but I am always getting the first item in the list as the selected item. This is what I am currently working with:
Code:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
I have set up an email function where a user of my website is able to send an email from the webpage including subject field and email body this allows the user that is logged in to select an email address from a drop down menu, once the email send button is clicked this will send an email to whatever email address in the dropdown menu has been selected. I want to be able to incorporate the option to send to multiple contacts such as a class list. I have set up a grid view that pulls information from the database this shows the contacts name, email address and also has a check box column.
I have set up a select all for the checkbox; I want to set up that if a checkbox is selected then the email will be sent to that person in question, so they could send an email to one, many or all users. Here is the vb code for on the email send button at the moment. I know that it has to do with the myMessage.To.Add(TxtBxEmail.Text). But instead of selecting TxtBxEmail.Text that contains the one email address from the drop down menu. I wish to be able to select any email addresses from the grid view that have been selected. This is in VS 2010 VB.
I have a table MemberProfile with columns FirstName, LastName, Gender and ComplexionCode.here iam displaying complexioncode as a dropdownlist with values fair, very fair, brown and when user selects a value I want to insert that in to table
I have creted a class( LookUpCodes) and written following code
public static IEnumerable<ComplexionCode> ComplexionCodes { get
[code]...
now when I click the button FirstName, LastName Gender are inserting in to the table. only Dropdownlist( ComplexionCode ) value is not inserting.
I am having trouble with DropDownList (and/or DropDownListFor) when using TemplateInfo's HtmlFieldPrefix in a strongly-typed view. DropDownList properly selects the value from the model when the prefix hos not been site. Once I set the value of HtmlFieldPrefix, the value from the model is not selected in the drop-down list.
I am using .NET 3.5SP1 and ASP.NET MVC 2 RC2.
Model:
public class TestModel { public string Text { get; set; } public string Option { get; set; }
[Code]....
Is there something I should be doing differently to have the proper value selected in the drop-down list?
Im working on an ASP.Net web forms application, where I have a form and the Index is working correctly, until I select a value from one specific control, a dropdownlist. After that no matter what control I am on if I press TAB it will go to the URL/Address Bar, from there to the search bar and then again to the URL bar...
I have several asp dropdownlists that are populated from a database. I would like it so that when an item is selected it opens a seperate page depending on the selection.
[Category("Settings")] public int ClientID { get { return Int32.Parse(DropDownList1.SelectedItem.Value); } set { DropDownList1.Items.FindByValue(value).Selected = true; } }
Getter commonly is being called by ControlPameters in SqlDataSources on pages with this control.
Setter - from markup: <uc:UserControl1 runat="server" ClientID='<%# Bind("ID") %>' />.
Why does setter from Bind is called earlier then PreRender? And DropDownList is empty and item selecting doesn't work! How to workaround this behavior?
I inherited a site which I am in the middle of updating which has a DropDownList and a RangeValidator assigned to it. The data is bound to the dropdown on Page_Load. The values are retrieved from the database so the value property of each item is set to the unique ID of the item in the DB.
The RangeValidator looks something like:
<asp:rangevalidator id="ddRangeValidator" runat="server" ControlToValidate="ddMenu" ErrorMessage="Please select value in range" MinimumValue="1" MaximumValue="100000" Type="Integer">*</asp:rangevalidator>
I have a method which automatically populates this value in jQuery e.g.
$("#ddMenu").val("An Option");
This works, however, when I try to post the page the range validation fails. Then even if I manually select that value, or select another valid value it still won't validate. The only way to make it validate is to select non-valid value and then re-selecting a valid one.
Here is the data binding code:
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load, Me.Load
If Not Page.IsPostBack Then Dim ds As New DataSet() Dim myDbObject As New myDbObject() ds = myDbObject.ToDataSet() // retrieves all objects from the database
I have a dropdownlist that controls what the users see in the gridview. I want to be able to have the users select "All" as an option. For example the drop down would for years would show: All, 2010, 2009, 2008. How do I code for the user selecting "All"? I am using ASP.NET 3.5 and C#
The intension is to get the all text file names in the drop down present in a particular location. When a user selects any filename from the drop down, it will show the data which is in that particular text file in a GridView.
I've done both the steps and it's almost complete but i stuck on a small issue. Probably because of non-usage of ASP.NET for a long period of time. The problem is, the drop down only selects the default value not other values.Here's my code for DropDown Selected Index Change
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { DirectoryInfo di = new DirectoryInfo(@"C:myLogs");
public class SectionModelBinder : DefaultModelBinder { public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { var value = bindingContext.ValueProvider.GetValue(bindingContext.ModelName); if (bindingContext.ModelType.IsAssignableFrom(typeof(Section)) && value != null) { if (Utilities.IsInteger(value.AttemptedValue)) return Section.GetById(Convert.ToInt32(value.AttemptedValue)); else if (value.AttemptedValue == "") return null; } return base.BindModel(controllerContext, bindingContext); } }
Now within my controller i can say:
[HttpPost] public ActionResult Create(FormCollection collection) { var category = new Category(); if (!TryUpdateModel(category, "Category") return View(new CategoryForm(category, _sectionRepository().GetAll())); }
This validates nicely and the correct value for the section is assigned when the model is updated, however it does not select the correct value if another property doesn't validate.
I have 2 Dropdown(say "DD1", "DD2") and 1 Listbox(say "LB") in my web form,value of the 3 controls depend on each other.
"LB1" is dependent on "DD2" value, "DD2" is dependent on "DD1" value.
I want that if user selects "LB1" without selecting "DD2", it should give a message that "please select DD2 first"similarly if user Selects "DD2" without selecting "DD1", it should give a msg that "Please select DD1 first" ,using ASP.NET C.
In my project requirement user wants to enter a manual entry if they can not find an item in the drop down list.
Right now what I am doing is:
I set the dropdown list autopost back true and on selectedchanged event I am hiding the drop down list and showing a text box to enter a manual entry...
This is working perfect and no problems..
but the drop down list needs to change to a text box on only selecting a "unknown" option in the list...all other list items are doing unnecessary post back to the server with no use...
The following example displays a modal dialog box when the user clicks the button.What changes do I have to make to get it to display the dialog when a selection is made from the dropdownlist?
Note that if I set the TargetControlID property from "Button1" to "DropDownList1", teh dialog box is displayed when the dropdown is DROPPED rather than when a selection is actually made.
I have a problem with CascadingDropDown... I have two related comboboxes, where the second is a slave of the first (e.g. country the first, cities the second). What I want is that if I select one country from combobox 1 then the second must be "filtered" by that selection (it should display all the cities inside the selected country, and the actual CascadingDropDown implementation is OK), but if I leave the combobox 1 in the default option (e.g. "Please select a country") I want the second to display all the cities I have in the database. The problem is that when selecting default option for combobox 1 the second combobox is disabled and a postback to my webservice never occurs.
