Dropdownlist - Dropdown List In Codebehind Versus In ASPX Page
Feb 17, 2010
I am generating a dropdown list in codebehind and cannot get the selectedindexchanged event to fire automatically. It works fine when put directly into the ASPX page, but I need it to be in the codebehind.
Does anyone know how to do this so when I select something the 1st dropdown and the 2nd one becomes visible and populates list from a Select statement. I really need help on how to do in an aspx and not on the code behind page.
when i click the dropdown list it is postbacking(since i made auto postback=true). on that time i am unable to get the selected value from dropdown list.
i want to know, if is better to make an entire page in the aspx file or in the aspx.vb file. If you have to decide, which one do you choose? ie in aspx:
Code: <asp:Table ID="Table1" runat="server" Width="980"> <asp:TableRow> <asp:TableCell> SOME TEXT </asp:TableCell> </asp:TableRow> </asp:Table> ie in aspx.vb: Code: dim tabla as new table tabla.id = "Table1" tabla.width = 980 dim fila as new tablerow dim celda as new tablecell celda.text = "SOME TEXT" fila.cells.add(celda) tabla.rows.add(fila) form1.controls.add(tabla)
In ASP.NET if the code and the asp.net markup is in one ascx file for example for a user control,would it perform poorly compared to a User control with Code Behind using a cs file and a designer.cs file?
there I have a situation where I need to make to call to a normal .aspx page from asp.net mvc web application. How can I make this request and get data back from the page. the data will be returned on on the page_load event of the .aspx page
I have an <%#Eval("FirstName")%> in the aspx page, I want to replace "FirstName" to <%#Eval(employee.FirstName)%> but "employee" object is instantiated in the codebehind like this:
Public employee As New Employee
How can I call this object in the aspx page? Should I can create an "employee" in the aspx? if so, how to do that.
How do you call a codebehind/class method from a gridview in an aspx page? Also, I need to pass the value of databound column to that method. Is this possible?
I am working on a web form using VS 2010. The controls I've added previously to this form will show in the drop down list in code behind and are available to add events too. However any new controls I've added for last week or so are not visible in the list. I cannot access their events. I have scoured the forums and tried everything I can think of, nothing works.
I have many controls on my form, but in particular, I have 2 dropdownlists. 1 dropdown list has 2 values, and each value controls what the second dropdownlist displays. This is an edititemtemplate and both dropdowns have the selecteditem set via '<%# Bind("fieldname") #>' on page load.
THe problem is, if I change the value of the first dropdown, it errors out because the second dropdwon has a bound value that is no longer acceptable.
Can I cancel the bind of the second control, if the the first one is changed? I would like to cancel the bind, and update the values by using a different datasource depending on the value of the first dropdown or hardcode the new values.
If Dropdown1 has a value of "A" for example Dropdown 2 Shows Values "1", "2", "3"
If Dropdown 1 has a value of "B" , Dropdown2 Shows Values "4", "5", "6".
It binds fine initially, but if I change Dropdown1 from A to B, I want Dropdown2 to show the new values, maybe with a default of "Select an Item" and not error out b/c it's attempts to bind a value of 1, 2, or 3.
I have been trying to call a vb.net function in aspx page how can i do that?. I have done it in C# by
<td><#%GetItemIndex(Container.ItemIndex)%></td> its working fine in C# but in vb.net it says GetItemIndex not declared.
and trying to convert (rptpages is a repeater)
rptpages.Itemcommand += New RepeaterCommandEventHandler( rptpages_ItemCommand1) from C# to VB.net but i dont see itemcommand property in VB.net for the repeater.
I am stuck at this point "Displaying a dropdown list of Categories with a --None -- Option. I want the gridview control to display 2 dropdown list one in read-only mode and the other in edit mode. When a record is in read-only mode, the dropdownlist's enabled property will be set to false."When it's on a read-only mode, it doesn't display the selected Category. it shows but the "No Category". When i click on edit to edit or change category, it doesn't display the selected category.
The example is given below( I am reading the book Sams Teach yourself ASP.NET 2.0 by Scott Mitchell. page 628)
<asp:Label ID="UserIdValue" runat="server" Visible="False"></asp:Label> <asp:SqlDataSource ID="picturesDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT * FROM [Pictures] WHERE ([UserId] = @UserId) ORDER BY [UploadedOn] DESC" DeleteCommand="DELETE FROM [Pictures] WHERE [PictureID] = @PictureID" InsertCommand="INSERT INTO [Pictures] ([UserId], [CategoryID], [Title], [Description], [UploadedOn]) VALUES (@UserId, @CategoryID, @Title, @Description, @UploadedOn)" UpdateCommand="UPDATE [Pictures] SET [UserId] = @UserId, [CategoryID] = @CategoryID, [Title] = @Title, [Description] = @Description, [UploadedOn] = @UploadedOn WHERE [PictureID] = @PictureID"> <DeleteParameters> <asp:Parameter Name="PictureID" Type="Int32" /> </DeleteParameters> <InsertParameters> <asp:Parameter Name="UserId" /> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="Title" Type="String" /> <asp:Parameter Name="Description" Type="String" /> <asp:Parameter Name="UploadedOn" Type="DateTime" /> </InsertParameters> <SelectParameters> <asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text"/> </SelectParameters> <UpdateParameters> <asp:Parameter Name="UserId"/> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="Title" Type="String" /> <asp:Parameter Name="Description" Type="String" /> <asp:Parameter Name="UploadedOn" Type="DateTime" /> <asp:Parameter Name="PictureID" Type="Int32" /> </UpdateParameters> </asp:SqlDataSource> <br /> <asp:SqlDataSource ID="categoriesDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT [CategoryID], [Name] FROM [Categories] WHERE ([UserId] = @UserId)"> <SelectParameters> <asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text" /> </SelectParameters> </asp:SqlDataSource> <br /> <asp:SqlDataSource ID="maxPictureIDDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT MAX(PictureID) FROM Pictures WHERE UserId = @UserId"> <SelectParameters> <asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text" /> </SelectParameters> </asp:SqlDataSource> <br /> <asp:Label ID="cannotUploadImageMessage" runat="server" Text="The photo could not be added to your album either because you did not specify a file to upload or the file specified was not a JPEG image with the file extension .JPG"></asp:Label> <br /> <asp:DetailsView ID="dvPictureInsert" runat="server" DataSourceID="PicturesDataSource" Height="50px" Width="125px" AutoGenerateRows="False" CellPadding="4" DataKeyNames="PictureID" DefaultMode="Insert" ForeColor="#333333" GridLines="None"> <AlternatingRowStyle BackColor="White" /> <CommandRowStyle BackColor="#D1DDF1" Font-Bold="True" /> <EditRowStyle BackColor="#2461BF" /> <FieldHeaderStyle BackColor="#DEE8F5" Font-Bold="True" /> <Fields> <asp:TemplateField HeaderText="Picture"> <InsertItemTemplate> <asp:FileUpload ID="imageUpload" runat="server" /> <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="imageUpload" Display="Dynamic" ErrorMessage="There was no file selected" ValidationGroup="PictureAdd"></asp:RequiredFieldValidator> </InsertItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Category" SortExpression="CategoryID"> <EditItemTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("CategoryID") %>'></asp:TextBox> </EditItemTemplate> <InsertItemTemplate> <asp:DropDownList ID="pictureCategory" DataSourceID="categoriesDataSource" runat="server" DataTextField="Name" DataValueField="CategoryID" SelectedValue='<%# Bind("CategoryID") %>' Visible='<%# Bind("CategoryID") %>' AppendDataBoundItems="True"> <asp:ListItem Selected="True" Value="">-- Select Category --</asp:ListItem> </asp:DropDownList> </InsertItemTemplate> <ItemTemplate> <asp:Label ID="Label1" runat="server" Text='<%# Bind("CategoryID") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Title" SortExpression="Title"> <EditItemTemplate> <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Title") %>'></asp:TextBox> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Title") %>'></asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1" Display="Dynamic" ErrorMessage="you must provide a name for the title" ValidationGroup="PictureAdd"></asp:RequiredFieldValidator> </InsertItemTemplate> <ItemTemplate> <asp:Label ID="Label2" runat="server" Text='<%# Bind("Title") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Description" SortExpression="Description"> <EditItemTemplate> <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Description") %>'></asp:TextBox> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Description") %>'
I have applied nested master page to some page. Now i want to bind drop downlist from value selected in dropdown list in master page of master applied to that page.
the hierarchy of pages is
mypage.aspx -> main.aspx -> inner.master
I want bind dropdown list in mypage.aspx from from value selected in dropdown list in inner.master
I need a develop a smart dropdown list for an inhouse application
Let assume, i have a dropdownlist with the following values:
ABC EDF XYZ A123 B456
Now when the user types A in the drpdownlist (we can type anything onthe dropdownlist, but we can superimpose a textbox on it), the dropdwn list should sort itself and show only ABC and A123.
I have a created a form using a user control. One of the dropdownlists in the form is populated after the user makes a specific selection from another dropdownlist...i.e. a dependent dropdown list. This is triggered using the SelectedIndexChanged event handler on the controllling dropdownlist.
The dependent dropdownlist gets populated correctly, but when I choose one of the options and go to submit the form, the dependent dropdown list is reset and doesn't maintain the selection that was made.
The controlling dropdown list ID is "level". The dependent dropdown list ID is "EnrollmentSize".
The "EnrollmentSize" DDL only losses the option that was selected. The DDL is sitll populated with all the correct values. It only losses the option that was selected and goes back to the first option...i.e. "Select..."
The viewstate on the page is enabled and all the other form values are maintained. It is only happening with the EnrollmentSize ddl.
I've set breakpoints and tried debugging and I do see that the EnrollmentSize.SelectedValue is an empty string, but I don't see why or where that is happening in the button click event
I thought it had something to do with EnableViewState,but that is set to true and has no bearing. Everytime I try to submit the form, the "EnrollmentSize" DDL is reset and doesn't maintain the option that is selected.
I have 2 drop down lists.I have a very simple dropdown list #1 that diplays a title and holds an id value which is a GUID.I know it is getting this value and sending this value as I tested sending it to a label.I have the dropdown list #1 to autopostback to dropdown list #2 that "Is supposed to get" another title and value based on the GUID value of the first dropdown list. for some reason it wont return anything. I have done 100's of these but never based off a guid value.I assume the value needs to be converted to guid before selecting it in the second dropdown list.How can I do this? or is there something I am missing?
I created a Site.Master page for my website. On the site.Master page I created a header that holds a dropdown list of companies. I was hoping that this dropdown list would be available to all pages, however the first page I made was a page with a grid view. I wanted to use the header dropdown list as one of the parameters to fill the gridview. That option does show up. I have all of the control on that actual page available to bind to, but not the Site.Master page.