C# :: WPF Collection Not Updating With Observable-collection?
Mar 19, 2014
I have a WPF project where I am using the entity framework. I have switched all my collection types to ObservableCollection and I am also using the PropertyChanged event. The only way my collections update is if I close the application then restart it. I got to the point where I just created a new application with 1 entity and 1 combobox to display a collection and I still can't get the collection to update. In my code below I am calling the AddCustomer method to add a customer name to the Customers ObservableCollection without success.
class ViewModel:INotifyPropertyChanged {
Model1Container context = new Model1Container();
public ViewModel() {
Customers = new ObservableCollection<Customer>();
UpDate();
I have a window in WPF which I want the user to use to enter the information for a COM Port.
The intent is to populate two ComboBoxs from a two different ObservableCollection<string> which I am having no luck with.
I don't think that it is a DataContext issue, as I am able to get something from the ComRateList when the window opens, but nothing from BaudRateList. Either way I have included the way that the window is opened and DataContexts assigned...
When the code runs, the COM Port list is updated when the window opens - However, it is not updated when the user reclicks the ComboBox which was my intended behavour.
All the adds for the BaudRateList do not populate the ComboBox for the baud rates on start up, nor when the code is running.
When I step through the code, I can see all of the BaudRateList items being added... The window is called by the main window's datasource like so...
OpenSerialCommunication OpenView = new OpenSerialCommunication(); OpenView.Show();
This opens fine.
The OpenSerialCommunication.xaml is as follows: (Note that any business names have been replaced with [snip])
<Window x:Class="[snip].SerialCommunication.OpenSerialCommunication" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:serial="clr-namespace:[snip].SerialCommunication" Title="Open COM Port - [snip]" Height="300" Width="300"> <Grid>
I have a class that loads the contents of a XML file into their respective object types and stores those objects in a list. Each object has its own list of objects with properties the program will later modify.
The problem I am currently having is that after looping through the objects and modifying the necessary properties the modifications do not persist. This leads me to believe I am modifying a copy of the object rather than the object I think I am modifying. I am not sure why this is happening as I believe I should be modifying the object that is referenced in the collection.
What I have tried, I started using LINQ to get the object I am looking to modify. After a little more research I don't think this can work properly due to the LINQ query returning a new object(copy of the object). Currently I am using nested foreach loops which still are not behaving the way I expect as the properties I am setting are not making their way back to the original object.
The PopulateLogSheet() in the following class is where the problem loop is.
class ChillerCheckCollection { public List<Chiller> chillers = new List<Chiller>(); public void LoadChillers(string filePath) { var availableChillers = (from chiller in Xdocument.Load(filePath).Descendants("chiller") select new Chiller
[Code] ....
And here are the other classes referenced in the above class.
class Chiller { public IEnumerable<LogSheet> chillerLogSheet = new List<LogSheet>(); public int chillerID;
In my WPF application i have a SQL class which i am trying to use to store all of my SQL queries so far this is working fine for when i want to return one piece of data like this:
public string GetEnquiry_ContactName(int EnquiryID) { string ContactName = null; //Try to do the following if not then show the error message. try { //Create the SQL Connection SqlConnection cn = new SqlConnection(Models.M_GlobalVariables.GetConnection);
[Code] ....
But if i want to return a collection of data like this:
public ObservableCollection<CompanyNames> GetCompanyNames () { public class CompanyNames { public string CompanyName { get; set; } public CompanyNames(string name) { CompanyName = name;
[Code] ....
It does not work and i get 'Not all code paths return a value' and ''List_CompanyNames' is a 'property' but is used like a 'type''. But if i have it in my ViewModel like this:
//Code for the 'Company Names' dropdown box public class CompanyNames { public string CompanyName { get; set; } public CompanyNames(string name) { CompanyName = name;
[Code] ....
It works absolutely fine but the whole point of my SQL class is to have all my SQL code in that class instead of some of it in the ViewModel.
I have a program which generates lots of data points in 2D (x and y co-ordinates). Perhaps 1,000,000+ of these points. These are floating point numbers. The values all fall within a specific range -R/2 and +R/2.
I want to impose an 'imaginary' grid. Such that I can collect the number of each of these points falling within a specific grid location. The actual 'grid' size is variable.
Should I try and collate this data from my C++ program and then post-process it in some other s/w like matlab?
I seem to have reached a dead end in a program I am attempting to write.The purpose of the program is find the smallest, largest, and average values in a collection of N numbers. It needs to get the value of N before scanning each value in the collection of N numbers.I'm having trouble creating comparisons for each set. I have a feeling because of the way I structured my program, I'm unable to make a proper comparison. Maybe my approach was wrong as soon as I got to the for statement to loop N sets and N numbers.Here is my code so far:
Code:
#include <stdio.h> int main (void) { int num_sets, num_of_integers; int count, count2, set, sum = 0; int num, avg; }
[code]....
/* Here is where I would continue to attempt to make a comparison between sets to determine smallest to largest */
I am struggling with how to efficiently design my class objects to support the outlining of a collection of items. The collection would be sorted but would also have the ability to indent and outdent individual items representing a Parent and Child relationship (see attached).
An item could indent up to 5 levels deep. A summary level would be considered a Parent while items below the summary level would be consider as children.
I am currently just trying to update a record in a SQL database.I can add a record and delete a record just fine but when I go to update I get no errors but it just doesn't update.
Here is what I have and done coding for hours trial and error
private void btnAddProd_Click(object sender, RoutedEventArgs e) {//validate method // product = new Product(txtProductName.Text, Convert.ToDecimal(txtProductCost.Text), txtProductType.Text); product = new Product(); MakeProduct(product); if(modify) { Product theOneAndOnly = new Product();
I want to search for the "movie_code" and change the [movie_status] from Active to Inactive.
So lets say for example i have a movie code 12345 saved in my movie file. I want to change the value from "Active" to "Inactive"for argument sake.
This is the code i was trying to do it with:
FILE *movie_fp; movie_fp = fopen("movie.dat", "r+b"); int m_code; MOVIE movie_data; printf("*** Welcome to the movie updater! *** "); if(movie_fp != NULL){
I've just integrated the Windows SDK V7.0A into my VS2005 application, and I'm getting the dreaded "Application configuration error" when I try to run it on an XP machine.
It runs fine on the development machine, and some customer machines (Win7 and Win8), but will not run on XP due to missing/incorrect version dlls.
I've rebuilt all my libraries, but still no joy.
So, my first question is - If I upgrade the Windows SDK to V7.0A, do I also need to use MFC 10 and msvcrt10, or can I stick with MFC 8?
The next question is, how do I find out which dlls are missing, and which libraries or other dlls are requesting the missing versions?
I am writing a program that manages a group of tool bins. This group is handled as an object that is an array of two element structures called InvBin. I initialize the bins with data from a file which contains the descriptions and initial quantities. I also have functions to add or subtract items from a bin and a function to display a report of the description and quantity of all of the bins.
The add and remove functions work correctly based on the cout statement in the functions, however when I display the report, it displays the initial quantity instead of the new quantity. In addition, when I use the add and remove functions again on the same bin, they use the initial quantity.
These are the add and remove functions and the report function from the main program.
Code: //Adds an item to a bin void addItem(HANDLE screen, BinManager tools, int &count) { int binNum; int addNum; system("cls");
I am having trouble updating my global pointer in the following code,
Code: #include <iostream> using namespace std;
struct RB{ RB()=default; RB(int clr):color(clr) { } int color;
[Code] ....
The problem is, at line where I compar y==Tnil, It is evaluating to false at the first insert. But It should be true. again, after ending the function, T again becomes equal Tnil, as a result , none of the is being inserted.
Code: #include<stdlib.h>#include<stdio.h> #include<unistd.h> #include<math.h> int main(void) { double N, NG, LG, epsilon, root; // setting all variables to type double
[Code] .....
The goal is to create a program to calculate the square root of a number provided by the user to an error tolerance 0.005
Looking around i fond the Code: fabs(NG - LG) < epsilon); section that was very similar to what i was using, but if this is better im down for that.
My issue, from what i can see, is the updating of the values of LG. if the test for error tolerance fails then LG needs to take on the value of the results of NG.
Now I am not 100% that is the point of failure due to the fact the script does calculate the root properly, but it never exits the program once it reaches the tolerance level.
Code: imac:ENG-3211 user$ ./hw_4_1
Please enter the number you wish to find the square root: 4
This code is working totally fine. Right now, I'm trying to update a specific data from the student info. Let's say I'm trying to update my student number of Daniel. So, in this case, I want to replace 6744590 to some other student number. I think I have to use fseek() or rewind() and use fputs() but, I don't know how I should decide where to look.
The program will grade a series of exams and then print a grade report for students in a course.
Input: An instructor has a class of students each of whom takes a multiple-choice exam with 10 questions. For each student in the class, there is one line in the input file. The line contains the answers that student gave for the exam. The input file named "grade_data.txt" will have the following format:
line 1: the key for the exam (e.g.) bccbbadbca
lines 2-n: a set of answers. You know you are done when you get to a line with no data.
Note: You will not know in advance how many exams you have to grade and you don't need to store the exam answers in your program.
Processing: The program is to read the input file and grade each exam and print out the score for that exam. You will also keep track of how many students earned each score (0-10) and print a report after the grading.
Output: Here is an example of how the output might appear. You will write the report to an output file named "grade_report.txt"
What I am having trouble with is the second part of the program. I have already figured out each grade for each student. The part I am having trouble with is updating the array every time that it gives me a student score so that I know how many people made a 10, how many made a 9, etc.
I have a datagrid, which has a column called Status. In the database, the field is a text field that can have the values up, down, or danger.
I needed to display the status as a "light" as per client request, so I have a StatusToImageConverter class that receives the status, and returns the proper image to display in the datagrid column. Works fine.
Now the issue I am having... I have a combo box above the datagrid for the user to filter the results if desired. The filtering works fine, but the newly displayed devices do not have their status light. In the Status column, nothing appears after the user filters. I think it may have to do with the fact that I am not re-initializing the datagrid, but just refreshing it? That's just my educated guess.
XAML: In the UserControl Resources:
<local:StatusToImageConverter x:Key="ImageConverter" /> In the DataGrid Control: <DataGridTemplateColumn Header="Status" IsReadOnly="True"> <DataGridTemplateColumn.CellTemplate>
So I am working on making a game. The first thing I did was make a window class. This correctly makes the window and displays it.
Now, I run my game loop and it just freezes the window and shows the Application has stopped working message box. I believe this is because the Window is not actually being updated.
My game loop however, looks like this.
bool run = true; while(run) { Window::Render(); if (Window::IsCloseRequested())
I just wanna update my database with one click only.
I do for update my database from datagridview1 but it shows a error like this :
Unhandled exception has occurred in your application . If you click Continue, the application will ignore this error and attempt to continue. If you click Quit,the application will close immediately.
Update requires a valid UpdateCommand when passed DataRow collection with modified rows
I am working on a Windows application using Visual Studio 2012. One of the screens have a text entry field for the user. Instead of using a standard text field control, am placing a image which looks exactly like a text field. Now what i want to do is, capture the key stroke and update this image with the characters entered by user.
The initial image shown to the user is "Blank_Text_Entry.png" and this is added to the resource as IDB_BLANK_TEXT_ENTRY.
This is a rectangular white image with dimensions 153 x 27, with a size of 250 bytes.
My goal is to be able to update this image dynamically based on key strokes by user and display it.
I have created an application that has bunch of buttons on top and i want to change the image when I click on the button. But unfortunately I can't get it to work.
Here is the code:
if (serialPort1.IsOpen) { tsbCommPortOpenClose.ToolTipText = "Open serial port"; closeCommPortToolStripMenuItem.Text = "Open serial port"; tsbCommPortOpenClose.Image = Image.FromFile("Red.bmp"); serialPort1.Close(); [Code] ....
The second one which changes the image to "image2" works fine. Here is the definition of image2:
When I do the same with the other image that I want to use, it won't work! I opened the project properties and added the image into the resources too, and it still doesn't work. It fails and says the file was not there. I've put a copy of the file in the root directory and one in "Resources" folder but it still doesn't work.
I am writing some code that takes a string of n letters, so a, or aa or aaa or aaaa...a and transforms these into d or dd or ddd or dddd...d by essentially counting. e.g aaaa -> aaab -> aaac -> aaad -> aaba and so on. Also technically the user inputs what the ending is whether it be d or e,f,g; however, for practical reasons counting up to dddd should work. My main issue is I am having trouble getting the letters correct. I get up to aadd and then once I go to abaa I have trouble getting the second to last a to switch correctly.
Code: #include<iostream> #include<string> #include<vector> using namespace std; int main() { vector<string> pleasework; string apple = "aaaaaa"; int end = apple.size()-1;
I have been searching through the forums and found a couple snippets of code and from that i came up with this. What i want to do is search for the specific movie code and then update the movie status from inactive to active (for argument sake).
Code: #include <stdio.h> #include <stdlib.h>
typedef struct SYSTEM_MOVIE{ int movie_code; int movie_dur; char movie_title[25];
On a project I'm working on, I need to update many QLabels very quickly. Each label needs to be updated at about 20 to 50 hertz and there can be over 50 labels at any given time. The problem I'm having is after running the program for about a minute, the labels freeze and the whole program crashes about 10 seconds later. If I comment out the setText() and setNum() calls and reroute the outputs to the console, it runs fine and never crashes. Why does calling SetText() and setNum() so quickly cause the program to crash and how can I prevent this?
I am supposed to update the value temp without using a return statement, or a global variable. I have never ran across a problem like this before and I am totally stuck. I think I'm missing something really simple and need a hint. Here is the code that was provided for "fixing".
#include "stdafx.h" #include <iostream> #include <cstdlib> using namespace std;
I have been creating this program for a student registration system. For the file handling So far I can write in to a file , view all records, and search a single record. now i got the problem with updating details . my coding is as bellow ..
