WPF NullReference Exception - Children Node Checkboxes To Be Set True
Nov 19, 2010
I have a TreeView with a parent node and two children node. Each of the nodes contain a checkbox stored in a TreeViewItem. I want the two children node checkboxes to be set to IsChecked=true when the user checks the parent node and I want the two children node checkboxes to be IsChecked=false when the user unchecks the parent node.
i need to check all child node when the parent node is checked and i had do research from the internet but it seem that i had a error which is Type 'MSComctlLib.Node' is not defined.do i need to import any reference? [code]
'this throws an "Object reference not set to an instance of an object"-Exception'
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A CType(obj, Boolean) would evaluate to False(just as CBool(obj)), i think because the compiler uses a helper function, but that is not my theme. Why does casting Nothing to Boolean evaluates to False, whereas casting an object that is Nothing to Boolean throws an Nullreference-Exception? Does that make sense?
I keep Getting a NullReferenceException Error but I have declared a NEW structure. See below:
Structure ISACReply Public RTD As ArrayList Public SAC As ArrayList Public DRT As ArrayList
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When I try to execute the subroutine "calltest" I get a NullReferenceException in the line that says " rv.DRT.Add("HELLO") " even though I have set rv to an instance of ISACReply using NEW.
I need to modify a xml file (actually a .rdlc report file) and add some nodes which have a lot of children nodes (and those children nodes again have children nodes). Actually they are almost the same strucutre, like this one:
and it will add my specified NS. (like I said, XElement.Parse(string) won't add it) So now I can construct the correct node. For my second problem I still can't figure out: I can't navigate to the target node by using the element name since it won't search for correct NS.
I'm working on a drag-and-drop method to copy items from a listview control to a treeview. I've got the drag and drop working, but I'm hoping to limit the ability to drag items that create a child of a child. Ideally, if someone drags an item from the listview to the Treeview and the drop the listview item over a child, it would drop the dragged item to the parent.
I am developing a windows application in vb.net and getting an error of system.nullreference exception.I am trying to insert data in the database, insertion occurs in the first go. But, when i stop the porgram and re-run, i get the exception.
I'm getting a design time NullReferenceException on Dim db As Database = DatabaseFactory.CreateDatabase()and I can't figure out what to do about it. Has anyone experienced this problem or know the solution?
I have a TreeView populated with some nodes, and some of those nodes have children. Is it possible that when the node, or child is selected that the entire node including the children be selected? I still want to deal only with the value of the root node, but for the UI I want the root + children to be selected.
So I have a TreeView and it has about 7 parent nodes that have 3-5 children each. All of these children nodes when click navigate to a URL. What I would like to do is have one parent node auto-expand based on the URL and the other parent nodes to collapse.
How can i programmatically create a treeview consisting of several nodes and each node has several children.I want to read the nodes and children from a table and fill them accordingly, so how can i do this?
I have a Listview listing multiple files with the following code
Dim index As Int16 = 0 For Each Item As String In NewFilenames ListView2.Items.Add(Item.Substring(Item.LastIndexOf("") + 1), index) index = index + 1 Next
I need to set all the checkboxes to true somewhere in this statement.
i got this code from the net , but i can't make this code work on the system i am programming so, i used the same codes to another system and it worked, when i tried using it to my system, it failed, so i started a new program and it still fails... what is wrong with my program? here is a sample of the code:
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whenever i run the program, it compiles, but when i click the commit button, this message appears "NullReference Exception was unhandled Object reference not set to an instance of an objects" and it points to .NewRow
I am getting this error when I try to print my report. Here is my print code.
Private Sub PrintToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PrintToolStripMenuItem.Click Dim Print_Dialog As New PrintDialog
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Here is my error: System.NullReference Exception: Object reference not set to an instance of an object.
When the following executes, I get the error 'NullReference Exception' - Object reference not set to an instance of an object. TestClass has Get and Set methods for the integer property TestWord.How should the following be changed to let me set TestWord in six elements of TArr?
Dim TArr(5) As TestClass For i As Integer = 0 To 5 TArr(i).TestWord = i * 10 Next
I have a master page than contains my ScriptManager. On a child page i have an updated panel. Inside the update panel there is a dropdowlist. When i set the autopostback=true i get OutofMemory Exceptions. All the time. also note that I have AjaxControlToolkit set on my web.config.
This is my problem.I have a field set up in MS Access to Boolean YES/NO, this field is populated when the user check a checkbox on a windows form. If the user check a checkbox, the value is written as checked in the data field (MS Access).The problem is when I search for the user information, I need the information from the Data base to populate(return) to the windows form. Example: If I enter a users phone number and the user data is present, the form gets populated with the information the user previously entered which was store in the database.Example: If the user selected checkbox1 and submits the form. When I search for the user info, the check box should check(populate) because the user had checked it on submit.Here is what I have done:
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I am getting the check value correctly in the database using a Boolean.Here is one of the errors I am getting. Unable to cast object of type
'System.Boolean' to type 'System.Windows.Forms.CheckBox.I am having trouble putting the codes in a code tag or block
How to count the total no. of asp.net checkboxes, checkboxes checked, no. of checkboxes remain unchecked in webform using vb.net ?I m using Visual studio 2008 with vb as a language ..I my webform i have 10 checkboxes...i wanna count total no. of checkboxes in webform in textboxes1 total no. of checkboxes checked in webform in textbox2 total no. of checkboxes remain unchecked in webform in textbox3?
Ok, so I know I have to change the labeledit to true but that doesn't change the selected node to be able to edit, so how does that work?
Along with renaming I have it set to that a user can add a node. So once the node has ben added how do I let them rename it as it is being added and without being a prompt or inputbox? So lets say I cam clicked on a parent and they click add node, it adds it to parent but I have it so it is default "New" but I want them to edit it as it is added. I think it will be along the same lines as clicking on one and rename but I have to start some place.
I am attempting to grab an attribute from an XML file and place it in a VB Class as a string. However when i try to run the program, I get a Null Reference Exception on line 21. why I'm getting this and not the placeID (line 2 on XML code)
Private Shared roomDoc As XmlDocument Private Shared rooms As XmlNode Private Shared roomList As XmlNodeList
I have a function that gets a string passed to it.When testing the function, I'm getting a null reference exception on the string parameter that gets passed to it, even though the string is not null, I don't understand why I'm getting this error.I used a dummy value to verify both the string parameter in the SelectSingleNode function and the newValue string parameter being passed to my function and they both contain values, so I don't understand why it's throwing a null reference exception. Just for clarity, the purpose of the function is to write values back to the nodes of an XML file.[code]
I have a function that gets a string passed to it. When testing the function, I'm getting a null reference exception on the string parameter that gets passed to it, even though the string is not null, I don't understand why I'm getting this error. I have a screen shot belowI used a dummy value to verify both the string parameter in the SelectSingleNode function and the newValue string parameter being passed to my function and they both contain values, so I don't understand why it's throwing a null reference exception. Just for clarity, the purpose of the function is to write values back to the nodes of an XML file.UPDATE
Private Sub setValue(ByVal nodeToMod As String, ByVal newValue As String) ''Test writing to xml config file Dim dummy As String = "Config/" & nodeToMod
i have a treeview which has a bunch of parent and child nodes preset at design time, there is 1 parent node tho which is called developer, that i want to add child nodes to at runtime.When the form first loads im trying to have it check a text file and for each line in the text file add the text/string from that as a child node tot he 'developer' parent node.
vb Dim reader As String = My.Computer.FileSystem.ReadAllText(Application.StartupPath() & "ConfigDevs.txt") Dim strs() As String = Split(reader, Environment.NewLine) For Each s As String In strs
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Thats what i have so far, how can i set it so 'Dim parentNode As TreeNode = ' points at the 'Developer' node?
The second Case in the first Sub is the one giving the error message.The second Sub is the part I (Removing the Label so that it can be recreated later) fix this code block? I do not know the correct way of removing or desposing a Label, as you can see the Label
Public Class Form1 '<<< Indecating if the app. is in Reading, Editingor AddingNew.>>> Dim ModeIndecator As String = "Reading"
I have a treeview which have a listimage. And it has imageselectindex property (image is yellow ball)My problem is : When i click any node, the image of that node shows imageselectindex . I only want thirth child node will show it. I dont want when i click at first node (rootnode) or child of roodnode , the yellow ballon shows.