Forms Data Controls :: Remove Databinding Of DropdownList When Another Dropdown List Changes?
Aug 27, 2010
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 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've got a class that implements IListSource and returns a generic List of ListItem objects (List<ListItem>). in this list one of the ListItems has the Selected attribute set to true.On the web page I have a standard asp:dropdownlist and I set it's datasource to the getList method of my class and databind it.The problem is that the databind seems to loose the selected Item and the first item in the generic list becomes selected.
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.
Basically when editing an item, I want to bind its ProviderId value to the DropDownList's select value.DropDownList is getting its list of values from other entity entity_List as you can see.
I have a gridview in which I have two drop downs. One is populated with values that are static, so I have a regular sub that does that in the code behind. I tried to add code for databinding the other ddl to a datatable. I cannot get this to work. It just comes up empty. My asp code is fine, and the datatable definately has data in it - just nothing gets populated.
One other thing - the code for the static ddl has worked fine, but when I add this other block (either to the same sub as that, or dow the rowdatabound event) the static one doesn't work either.
I am trying to create a Gridview in which I can update the Project Officer name in the Gridview from a DropDownList.
The Project Officer DDL comes from a seperate query (SqlProjectOfficerName) as the other information (SqlDataSource1)... as you can see below.
When I select EDIT, the DDL appears and I can select from the list of Project Officers, but when I select UPDATE, the name of the Project Officer doesnot change.
review the code below and assist as appropriate to write the Project Officer's name back to the table.
Bringing back to life an old post that I dont believe ever got solved: http://forums.asp.net/t/1562245.aspxThis may be an old thread .... but no answer was ever given ... and I too have a radio button list and DDL and am stuck in the EXACT same place. If I check one of the two data bound radio buttons, the DDL should repopulate with a different set of results. This works just fine EXCEPT .... the DDL cannot be databound. If I set SELECTEDVALUE of the control to a bind I get this error:Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.I have followed the advice on this page from various users, all to no avail....surely this can be done, and I assume quite simply. Anyone know the answer?
I have a formview that has several dropdownlists in the EditItemTemplate. Some of the dropdownlists are added using placeholders. I can add and populate their listitems without any problem. But when I update the record, none of the controls can be found--even though when I look at the page source they are there. I first strated out using asp:ControlParameter in my sqldatasource updateparameters, but even referencing the control as myform$mycontrol did nothing. So then I moved to code behind on the sqldatasource.updating event (code is attached). The only controls I cannot seem to bind to the update are those added via the placeholder.
[Code]....
The item at the dim statement is not an item added using a placeholder and does not get a null reference exception (I used that to prove during debbugging that I wasn't losing my mind)--however, all the items being used to get the parameter values are getting null reference exceptions and are added via placeholders. Here is the code I'm using to set up the dropdownlists:
[Code]....
how to get the value of these controls so they can be used in my update?
I have a databound dropdownlist and have a problem with the default value it selects.When I attempt to edit a record the dropdownlist shows the first value in the list rather than the current value. I want the dropdown list to display the current value.
I'm sure this is very simple but I'm very new to ASP.NET.
I m trying to stop the postback causing by ddl. I have tried the following code but still pb doesnt stop:
<script type="text/javascript" language="javascript"> var ddlSubCategory = document.getElementById("ctl00_m_g_73a5a887_bd36_4a37_966a_ed640c804a84_ctl00_ctl04_ctl09_ctl00_ctl00_ctl04_ctl00_ctl00_SubCategory"); //Get this form html source ddlSubCategory.removeAttribute("onchange"); //Here "onchange" attribute causes post back </script>
I m working on MOSS 2007. My project requirment is to fetch the data from list to gridview with check boxes in front of all rows. when we click the checkbox infront of rows then that rows will be move to another gridview & remove from first gridview. Then I have to search the rows by location. following is my code it fetches the list in gridview & move rows from one gridview to anothe
1. how to remove selected rows from gridview & list?
I have a webForm which host a gridview and a formview. The formview is used for showing/editing a record which the user Select from the gridview.
In the formview Edit template I used DropDownList controls with
SelectedValue='<% bind("datafield")%>'
for enabling the user easier interface. A few of the DropDownList controls need to have a list of 100 items and I want to load the items from code behind and not from the aspx.
I tried to update the DDL's from FormView.Load, FormView.ModeChanging, FormView.PreRender but nothing I am getting an error like this:
[code]....
How do I load the DropDownList controls with items BEFORE the form databinding occurs.
1. I am new to ASP and I can not get this to work:
2. I am Using a <asp:DropDownList in a <InsertItemTemplate> in a <asp:ListView
3. The dropdownlist during insert does not get polulated (it is empty) while the same construction and same datasource works in the edittemplate: <asp:DropDownList in a <EditTemplate> in a <asp:ListView
4. I noticed that filling the dropdownlist with a <asp:ListItem works; the insert list is populated. (not usable for me) In both cases I use the same datasource from the code behind like this : Edit:
can i enter a choice that is not in the dropdown list? Just like a combo box, there is a list of item but a user can still have an option to enter in the textbox. does a dropdown list also have this function? or if not is there a workaround?
I want to access a dropdown control value of each list item as soon as it is created. I tried with ItemCreated and ItemDataBound events but I am getting null contro when I try to access control as shown below:
I have a database with some data in. Now I'm trying to show that data on my page whit a ListView.
For each object from the database a ListView will generate a dropdownlist.
I also have a DataPager on my page and this is where the problem occurs.
Each object generated from the database has a field that may look like this example.: 1,2,3.
In my code now I´m trying to split this string of comma character and add new items to my dropdownlist.
This works as long as I do not have DataPager on. But if I choose to view an x number of pages at the time when the page loads, I have value in the dropdownlists, only on my first page.
How do i set a data source of a drop down list which is inside a grid view, snap shot of asp code given below , the Asp file name is DataEntry.aspx and there is method in the DataEntry.aspx.cs called DTB.BindData("Department"). i want to set the datasource to point to this method
my C# web application contain accessing of database on the basis of datas selected from a dropdown list.. and my pblm is i cant access the first entry from the dropdown, dropdown list contains different dates,when user select one date from dropdown it will redirect to another page.. the page shows details from database on the basis of this particular date.....my C# dropdown's selected index changed code is shown below:-
[Code]....
and HTML code corresponding to this is:-
[Code]....
i cant access the first data from dropdwn,even it cant redirect to target page.. other entries (the 2nd 3rd entrie etc) was accessible and it shows the details from database on the basis of that corresponding value(usually some date).
I have a small problem with drop down list. I have a aspx page which shows the information of a customer and there is an Edit button, which will take the customer to the edit information page. On the edit information page, I have drop down lists and I want the selected value in the drop down list to have the current value of the current customer on Page Load event.
I have packed the access 2007 project management database and moved it to SQL Server. I'm aware that SQL doesn't populate dropdown lists for the Status and completion Percentage columns. I have to have this done by April 21 and my professor is just now telling me he won't accept the textbox inputs due to data integrity and I don't have time to rebuild this entire site.
