Forms Data Controls :: Setting The Selectedvalue Where The Result Of The Query Is Null?
Aug 20, 2010
I have a query that references many tables, however the main record doesnt necessarily have records in the other tables. In my formview itemtemplate, i bind the values of the query but I'm getting an obvious error when the value is null. This is what I'm trying to do: (the field is a boolean btw). These fields are hidden so I don't really care if it gets assigned a temp value or something.
[Code]....
Error: BC30452: Operator '=' is not defined for types 'Object' and 'System.DBNull'.
I have this ListView that has a Drop Down List.Everything works fine (I think/hope) except that the drop down list are not showing its result correctly.This is the code.
Front-End [Code]....
The code behind consist of the page_load and the ItemDataBound [Code]....
I'm populating a dropdownlist in a formview with a different datasource from the formview's. I need to set the selected value according to the value in the formview's datasource but I'm having a hard time doing that.
Here's the code: <asp:FormView ID="FormView1" runat="server" DataKeyNames="ID" DataSourceID="SqlDataSource1"> <EditItemTemplate> [code]....
var query = from emp in dbEmp.Employees join dept in dbEmp.Departments on emp.DeptID equals dept.DeptID where dept.DepartmentName.Contains(this.TextBox1.Text) select new { EmpID = emp.EmpID, EmpName = emp.EmpName, Age = emp.Age, Address = emp.Address, DeptName = dept.DepartmentName };
if (query==null) Label1.Text = "no results match your search";
Everything works in the right way, but the label doesn't show the message when query result returns null. The label can show without condition(querry==null). So how to test if a var query result returns nothing?
i have asp page. i did the connection with connection string. the query is to search name, id and phone numbers. i wand to display these data in 3 textboxs. how can i display these results in textbox.
this is the connection code.
SqlConnection con = new SqlConnection(); SqlCommand cmd = new SqlCommand(); SqlDataReader reader; con.ConnectionString = "server=localhost;uid=sa;pwd=sa;database=mydatabase"; cmd.CommandText = "select ename, id phone from emp";
now i want to display these data in 3 textboxs. how can i do it.
I have a dropdownlist in DetailsView to which items are added programmatically during DataBound event. It is working fine in InsertItemTemplate, but in EditItemTemplate i am getting this error "'branchDDL' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value".
and right below that i have 1 condition to check for and then set the Text value of the 2 labels.hireMess.Text = "It Was Successfully!";hireEnd.Text ="You will be re-directed to your Pool in 10 seconds.";I compared the page to production and eveyrthing is the same and production doesnt have any issues.. not sure why its coming up null.The error comes up for the first label:Object reference not set to an instance of an object. 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.NullReferenceException: Object reference not set to an instance of an object.Source Error:
I have a ASP.Net webform with a DropDownList control. This Dropdown gets it's values from a states table in an ObjectDatasource. The Dropdown contains states spelled out.
If I try to set the drop down to: DropDownStates.SelectdValue = "Ohio"
I get an error that the value does not exist in the dropdown even though it does exist. But if I pad the value with the correct number of spaces to the right, it works like so: DropDownStates.SelectdValue = "Ohio " or DropDownStates.SelectdValue = "Michigan "
How can I either define the dropdown without trailing spaces in the value of the dropwdown or set the SelectedValue with adding trailing spaces?
When using SqlDataReader.NextResult for 2 queries I am trying to I check if the second query returns any rows, but whether it has any rows or not the repeater2 is never hidden/false . I am doing something like this:
I'm having a problem with my Linq to XML query. I'm getting the result data I want, but it's nested so deep that there must be a better way.Here is my XML:
[Code]....
I'm trying to get a list (simple string[]) of all Item IDs where Category Names contains "Other".Here is my Linq:
[Code]....
[Code]....
Here is a snapshot of my result from Visual Studio:The results I want are there ("item100", "item400", "item500"), but buried so deeply in the results var.
I have officially wasted about two days trying to figure out what the heck was going on with my asp.net page. I actually thought it was an issue with my updatepanel code, but after reading another post I was able to reproduce the same results. [URL]
I just manually added the following control to the page (no code behind for the listbox) and it is nested in an ajax tabcontrainer inside an updatepanel. If you set item 20 as selected the page flickers when loading that tab. I tried the css mentioned (style="overflow:hidden") on the tabcontainer,tab panel, update panel and dropdownlist, but no luck. Crazy select item 19 no flicker, 20 (which is actually the 21st item) and it does flicker. This is driving me insane. And yes this only occurs in FireFox ( running 3.6).
I have a WebForms page that has two DropDownList controls on it that both contain a range of temperatures from 60-80 degrees, one for heating the other for cooling. They are declared in the .aspx as:
When I try to set the selected value for each DropDownList using the values in an object containing data loaded from the database using:heating.SelectedValue = myHome.avgHeatingTemp.ToString(); cooling.SelectedValue = myHome.avgCoolingTemp.ToString();
The SelectedValue for both lists is set first to the value in myHome.avgHeatingTemp, then to the value in myHome.avgCoolingTemp. Heres what the values are for each variable after each step of the process of setting the SelectedValues:
Initial State heating.SelectedValue: 60 cooling.SelectedValue: 60 [code]....
In our asp.net web application we load the dropdown list boxes in the page load. We than set the SelectedValue of each dropdown list box to an object from session. We have event handlers for many of the SelectedIndexChanged events of the drop down lists boxes, but these do not get executed when we set the selected value programmatically.
Someone else mentioned this is by design, and only when a user manually changes the drop down list selected index, will the event get raised.
I would think this is a common scenario of wanting the selectedindexchanged event handled when setting the selectedvalue/selectedindex/listitem's selected property, of a DropDownList. What is the suggested way to handle this? Is there a significant drawback of creating a custom control inherited from DropDownList that has the functionality of raising this event when changing the SelectedIndex or SelectedValue?
I binded the dropdown from the table Languages, now it shows all the languages:
ViewData("Languages") = New SelectList(objLang, "SysLanguageID", "LanguageName")
Now when I click the edit then the dropdown should show the selectedvalue based on the languageId that is in stored in the Preferences table under the user.If i give the third parameter as the selectedvalue it is showing the selected value but it is not showing the other languages.
I have a databound dropdownlist on a page, where in the page_load I set the selectedValue (inside a 'not isPostBack').
Although the page displays fine and shows the correct item as selected.. inside the page_load if I try and get the selectedValue() and display it to the screen, I always get null... selectedIndex is -1.
I have a button, which when clicked refers to this ddl's selectedValue, and here it pulls through the the expected result.. so how come I can't see it immediately after setting it, while still in page_load?
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load dlCountryList.SelectedValue = "GR" Response.Write("*" + CStr(dlCountryList.SelectedIndex) + "*") End Sub
I have a bit of a problem with a DropDownList I am using. When the user changes the SelectedIndex, they get redirected to the same page, but with a query string on the end based on their selected value.
Because I'm not posting, and redirecting instead, the state of the dropdownbox is not saved, so it always defaults to the first one.But, if I save it in say a session, or set the selectedvalue according to the query string in Page_Load, when the user selects another listitem, the selection they have chosen is overridden by the selection delcared in Page_Load.
this is my sql query and its work fine in my code but it only check ParentDeptID IS NULL it not working when ParentDeptID field is empty how can i check it
("select DeptID,DeptName,(select count(*) FROM HrDept " _ & "WHERE ParentDeptID=sc.DeptID) childnodecount FROM HrDept sc where ParentDeptID IS NULL ", _ objConn)
However, in my button click event, when I check waht is the selected item's value (lstCategories.SelectedItem.Value, also lstCategories.SelectedValue) I find that the selected item is always null.
the user can only select one item in the list for what it matters. (SelectionMode = Single)
I want to populate a label with the employees name when they enter a badge number in the source page but im new to programming and don't know how to tackle this. The database connection has been established and it is successful. just an fyi this is for a time sheet application.
string Badge = "100000" + Request.Form["xBadgeTextBox"]; string Date = Request.Form["xWeekDropDownBox"]; string Hours = Request.Form["xWlengthDropDownBox"]; if (Badge != null) { string cmdquery = "SELECT EMPLOYEE_NAME FROM Employees WHERE Badge ='" + Badge + "'"; OracleCommand cmd = new OracleCommand(cmdquery); cmd.Connection = conn; cmd.CommandType = CommandType.Text; }
I have a repeater with a DropDownList in it. I set the datasource of this list in the itembound event en set the selectedindex. When I debug the selectedindex is set, but when the page is done loading for all the item the default item is selected.
I am trying to display this query result in an aspx page.
It is very slow in loading. Here is the query. The inner query inside the outer quesry is the problem.(Please see the underlined part in the query) - (If I remove that part it is very fast.)
select
top 500
--This column is the issue ,Governing_Class=( case when exists (select top 1 tqc.class_code from t_quote_class tqc inner join t_quote_class_premium tqcm on tqc.class_code =tqcm. class_code where tqc.appid=pi.appid and tqc.class_code not in('8742' ,'8810','7380') order by tqcm.premium_amt desc ) then ( select top 1 tqc.class_code from t_quote_class tqc inner join t_quote_class_premium tqcm on tqc.class_code =tqcm. class_code where tqc.appid=pi. appid order by tqcm.premium_amt desc ) ......... From tables
I have the following code which writes to a Gridview:
[Code]....
Using the same methods of connecting to the database, how can I amend this code to write the result of a second query (which only returns a number) to a label?
