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Text Box values chabged but the binding see it as null [duplicate]

I am working on some data collection forms in WinForms/C#. When the form loads, I am looping through a configuration and adding a new Binding to each of the TextBox controls; mapping the Text property of each TextBox control to specific string property on my POCO object.
public void BindTextBoxControls(dynamic entity, List<TextBoxConfig> textBoxConfig)
{
foreach (var config in textBoxConfig)
config.Control.DataBindings.Add(new Binding("Text", entity, config.PropertyName));
}
Everything has been working as expected, new records properly saving new values entered into the corresponding TextBox controls, TextBoxes populating with the correct values when reopened a previously entered records with the form, and updates to values in TextBoxes of previously entered records are getting the updated values set on the underlying POCO.
However, I started to layer in some business rules onto the form specifically to gray out/disable and clear out previously entered values in the TextBox based on other user input/activity on the form - things are not working as expected.
In a contrived example; a rule like if a Checkbox_1 is checked then TextBox #5 should not be valued (clear out any previously entered value and disable it from input). On my Checkbox_1 event handler for CheckedChanged, I specifically check if the Checkbox_1 is checked and if so, set TextBox_1.Text == null and TextBox_1.Enabled = false. This works as expected and on the form, I see any previously entered value cleared from the TextBox_1 and it becomes enabled.
private void chkCheckBox1_CheckedChanged(object sender, EventArgs e)
{
if(!chkCheckBox1.Checked)
{
txtBox5.Text = string.Empty;
}
}
However, when I debug and break on the save and inspect the underlying POCO's property that the underlying control is bound to after the method is called; the old value still persists on the object's property which the text box is bound to, despite the textbox having not value appearing on the form. When I reopen the form for that record, the old cleared out value is re-populated in the disabled TextBox. However, manually clearing out the value in the same TextBox or updating a value and inspecting the object shows the updated value after those operations are performed.
It seems like changing the Text value of a TextBox control (e.g. the Text property of a TextBox) in code maybe somehow be "bypassing" the DataBinding? I'm actually seeing the same/similar behavior when applying similar rules to "uncheck" TextBoxes programmatically within event handler methods - the CheckBox controls are also using DataBinding to boolean properties on the POCO.

When you setup databinding by this overload: Binding(String, Object, String), then the value of DataSourceUpdateMode will be OnValidation, which means when you modify the value of control's property using code or through UI, the binding will push the new value to data source only after Validating event happens for the control.
To fix the problem, use either of the following options:
Use another overload and set the DataSourceUpdateMode to OnProperetyChanged
OR, after setting the Value of the TextBox.Text call ValidateChildren method of the form.
Example - Set the DataSourceUpdateMode to OnProperetyChanged
public class Person
{
public string Name { get; set; }
public string LegalCode { get; set; }
public bool IsRealPerson { get; set; }
}
Person person;
private void Form1_Load(object sender, EventArgs e)
{
person = new Person() {
Name = "My Company", LegalCode = "1234567890", IsRealPerson = false };
NameTextBox.DataBindings.Add(nameof(TextBox.Text), person,
nameof(Person.Name), true, DataSourceUpdateMode.OnPropertyChanged);
LegalCodeTextBox.DataBindings.Add(nameof(TextBox.Text), person,
nameof(Person.LegalCode), true, DataSourceUpdateMode.OnPropertyChanged);
IsRealPersonCheckBox.DataBindings.Add(nameof(CheckBox.Checked), person,
nameof(Person.IsRealPerson), true, DataSourceUpdateMode.OnPropertyChanged);
IsRealPersonCheckBox.CheckedChanged += (obj, args) =>
{
if (IsRealPersonCheckBox.Checked)
{
LegalCodeTextBox.Text = null;
LegalCodeTextBox.Enabled = false;
}
};
}
Note - You can put the logic inside the model
Another solution (Which needs more effort and more changes in your code) is implementing INotifyPropertyChanged in your model class. Then when PropertyChanged event raises for your boolean property, you can check if it's false then you can set the string property to null.
In this approach you don't need to handle UI events. Also right after updating the model property, the UI will be updated; in fact implementing INotifyPropertyChanged enables two-way databinding for your model class.

ComboBox has DataSource set but is not displaying any items

I have a windows form with a ComboBox DisplayBox. In my ViewModel I now have a Property BindingList<MyObject> ObjectBindingList that I want to bind to the DisplayBox.
When I load the form, the DisplayBox does not show any text.
The property DataSource is set and holds a List of MyObjects when checking in the debug modus after the data download.
The property items always has a count of zero.
My code works as following:
On startup I set the databindings in the form class to a still empty List ObjectBindingList.
displayBox.DataSource = ObjectBindingList;
The DisplayMember and ValueMember were set in the ComboBox Properties in the GUI Designer.
Asynchrously the controller downloads some data (MyDataObjects) async. Then sets the BindingList<MyObject> ObjectBindingList in the ViewModel to the downloaded Objects through adding them.

Since I don't see all of the relevant code, I can only assume what's happening.
Probably, you don't see the data in the ComboBox, because you are creating a new BindingList when loading the data. But the ComboBox is still attached to the old empty list.
You initialize the data source with an empty list like this:
// Property
BindingList<MyObject> ObjectBindingList { get; set; }
Somewhere else
// Initializes data source with an empty `BindingList<MyObject>`.
ObjectBindingList = new BindingList<MyObject>();
displayBox.DataSource = ObjectBindingList;
Later, you load the data and replace the list:
ObjectBindingList = LoadData();
Now, you have two lists: the initial empty list assigned to displayBox.DataSource and a new filled one assigned to the property ObjectBindingList. Note that displayBox.DataSource does not have a reference to the property itself, therefore it does not see the new value of the property.
For a BindingList<T> to work as intended, you must add the items with
var records = LoadData();
foreach (var data in records) {
ObjectBindingList.Add(data);
}
I.e., keep the original BindingList<MyObject> assigned to the data source.
See also: How can I improve performance of an AddRange method on a custom BindingList?
To avoid the problem, I would be advisasble to make the property read-only (using C# 9.0's Target-typed new expressions).
BindingList<MyObject> ObjectBindingList { get; } = new();

It seems like when trying to update the ComboBox from a different thread than the main forms thread, the update did not reach the control.
I am now using the Invoke Method together with a BindingSource Object in between the Binding List and the control.
private void SetBindingSourceDataSource( BindingList<MyObject> myBindingList)
{
if (InvokeRequired)
{
Invoke(new Action<BindingList<MyObject>>(SetBindingSourceDataSource), myBindingList);
}
else {
this.BindingSource.DataSource = myBindingList;
}
}
I am expeciall calling the above function on a PropertyChanged event, that I trigger at the end of every call of the download Function.

Listview Add Items not appearing C#

I'm working on a small program as part of my A Level Computing course that is designed to track orders. It is written in C# using the Windows Forms.
I am having an issue where I enter all the information for a new order and then press OK and it should update the ListView with the information. I have my ListView in Detail view with 4 columns but nothing ever gets added to the ListView. The section of code that should add the items to the ListView is being executed and is not throwing any errors or causing the program to crash but nothing is being added. Its weird because I am using the exact same method that I used in my little prototype mock up but for some reason now it is not working.
All the things I've found on here or on the internet seem to suggest its an issue with the View mode of the ListView and I've tried modifying this property to no avail.
Any ideas why this section of code is refusing to add anything to the ListView?
//Create an array to store the data to be added to the listbox
string[] orderDetails = { Convert.ToString(id + 1), rNameBox.Text, dateBox.Value.ToString(), orderBox.Text };
//DEBUGGING
Console.WriteLine(orderDetails[0]);
Console.WriteLine(orderDetails[1]);
Console.WriteLine(orderDetails[2]);
Console.WriteLine(orderDetails[3]);
//END DEBUGGING
//Add the order info to the ListView item on the main form
var listViewItem = new ListViewItem(orderDetails);
ths.listView1.Items.Add(listViewItem);
If you need any more information just say. Apologies if this is in the wrong format or something this is my first time here.

Your problem is that your ListViewItem contains a string array and it has no useful way of displaying it.
What you should be doing (there are a number of ways of doing this, but here's one) is creating a class, OrderDetail, with an Id, a Name, a Date, and so on. Give it a ToString() method (public override string ToString()) which returns what you want to display, e.g.:
public override string ToString()
{
return this.Name;
}
Create an instance of OrderDetail and set its properties. Create ListViewItem giving it the OrderDetail instance and add to the ListView. Repeat for as many OrderDetail instances you want.
Cheers -
Added: code which works:
int id = 12;
string rNameBoxText = "rName";
DateTime dateBoxValue = DateTime.Now;
string orderBoxText = "order";
string[] orderDetails = { Convert.ToString(id + 1), rNameBoxText, dateBoxValue.ToString(), orderBoxText };
//DEBUGGING
Console.WriteLine(orderDetails[0]);
Console.WriteLine(orderDetails[1]);
Console.WriteLine(orderDetails[2]);
Console.WriteLine(orderDetails[3]);
//END DEBUGGING
this.listView1.Columns.Clear();
this.listView1.Columns.Add("Id");
this.listView1.Columns.Add("rName");
this.listView1.Columns.Add("Date");
this.listView1.Columns.Add("Order");
this.listView1.View = View.Details;
//Add the order info to the ListView item on the main form
var listViewItem = new ListViewItem(orderDetails);
this.listView1.Items.Add(listViewItem);

Why does the ListView refuse to display its columns, items, and subitems (shows only Group)?

The ListView seems to be as cantankerous as a polecat and as temperamental as a [elided by the P.C. police]
With help from - and others, I was able to get a ListView working just as I wanted
it to
(http://stackoverflow.com/questions/11423537/how-to-add-subitems-to-a-listview).
Now I'm converting that simple demo for use in a real app.
I create the columns in the form's Load event:
listViewGroupsItems.Columns.Add(colHeadName);
listViewGroupsItems.Columns.Add(colHeadRate);
...but they don't display. However, there is a blank line above my first item. So why are no text values being displayed. Are they "there" but invisible? Why would they get wiped out?
Anyway, what I want to see is:
column1Title column2Title
Group1Name
Item subitem
Item subitem
Group2Name
Item subitem
Group1Name
Item subitem
Item subitem
Item subitem
Item subitem
...but what I actually see is just:
[blank line]
Group1Name
...that's it!
The ListView's View property is set to Details; otherwise, all of the properties are the default values.
My listview code is:
private void AddGroupsAndItems() {
Dictionary<string, string> GroupsDict = PlatypusData.GetGroupsForTopLevel(Convert.ToInt32(labelTopLevel.Tag));
int currentGroup = 0;
foreach (KeyValuePair<string, string> entry in GroupsDict) {
string GroupNumber = entry.Key;
string GroupName = entry.Value;
listViewGroupsItems.Groups.Add(new ListViewGroup(GroupName, HorizontalAlignment.Left));
Dictionary<string, string> ItemsDict = PlatypusData.GetItemsForGroup(GroupNumber);
foreach (KeyValuePair<string, string> itemEntry in ItemsDict) {
string itemID = itemEntry.Key;
string itemName = itemEntry.Value;
ListViewItem lvi = new ListViewItem(string.Format("{0} ({1})", itemName, itemID));
lvi.SubItems.Add(PlatypusData.GetDuckbillNameForItemId(itemID));
listViewGroupsItems.Items.Add(lvi);
listViewGroupsItems.Groups[currentGroup].Items.Add(lvi);
}
currentGroup++;
}
}
UPDATE
I changed my code in the form's Load event from:
var colHeadName = new ColumnHeader { Text = Resources.RateRequestForm_RateRequestForm_Load_Billing_Account_Client, Width = 160 };
var colHeadRate = new ColumnHeader { Text = Resources.RateRequestForm_RateRequestForm_Load_RatePlan_ID, Width = 120 };
listViewCustomerBillAccountsClients.Columns.Add(colheadName); //colHeadName);
listViewCustomerBillAccountsClients.Columns.Add(colheadRate); //colHeadRate);
...to:
ColumnHeader colheadName = new ColumnHeader();
ColumnHeader colheadRate = new ColumnHeader();
listViewCustomerBillAccountsClients.Columns.Add(colheadName);
listViewCustomerBillAccountsClients.Columns.Add(colheadRate);
...and it made no difference at all.
It would seem that the ColumnHeader constructor should be able to take a string of what it should display, but even when I do that:
ColumnHeader colheadName = new ColumnHeader("This");
ColumnHeader colheadRate = new ColumnHeader("That");
...there is still no change (according to Intellisense or whatever it's called, the string arg is an ImageKey, but I thought I'd try just out of thoroughness/frustration.

Late to the party, but I've just spent some time trying to solve a similar problem. The answer I found was that when clearing the list before filling, you must use
listviewGroupItems.Items.Clear();
not
listviewGroupItems.Clear();
The ListView.Clear() method clears everything from the control--including the columns

I had the same issue today. I had coded listView.Clear() as user2867342 mentioned. I needed to change that to listView.Items.Clear(), but that did not make the columns appear. The columns were there, and I could click on them and resize them, but they were completely blank.
I had a ListView set to Details mode. I also had set the OwnerDraw property to true, because I wanted to paint my own progress bar column. MSDN says the following about the OwnerDraw property (emphasis mine):
A ListView control is normally drawn by the operating system. In order
to customize the appearance of ListView items, subitems, and column
headers, set the OwnerDraw property to true and provide a handler for
one or more of the following events: DrawItem, DrawSubItem,
DrawColumnHeader. This is called owner drawing. When the View property
is set to View.Details, all three events occur; otherwise, only the
DrawItem event occurs.
I had to implement the DrawColumnHeader event. In my case, the defualt worked fine, so the method sets the DrawDefault event parameter to true. After implementing this event handler, the column headers appeared correctly:
...Windows.Forms designer code...
listView.DrawColumnHeader += new DrawListViewColumnHeaderEventHandler(this.listView_DrawColumnHeader);
...
private void listView_DrawColumnHeader(object sender, DrawListViewColumnHeaderEventArgs e)
{
e.DrawDefault = true;
}

You're missing column headers in your code. (fixed)
Per the MSDN:
"If your ListView control does not have any column headers specified and you set the View property to View.Details, the ListView control will not display any items. If your ListView control does not have any column headers specified and you set the View property to View.Tile, the ListView control will not display any subitems."
Granted, you'll probably need to make more adjustments than what you see in my SS, but it at least answers your question as to why you are getting blanks.
Edit (Changed lines, although changing them back to your code didn't skew my successful results):
lvi.Group = listViewGroupsItems.Groups[currentGroup];
listViewGroupsItems.Items.Add(lvi);

One more thing to check I just found:
OwnerDraw must be false.
Copy & Paste from previous project and forgot that I used OwnerDraw

unable to edit DataGridView populated with results of LINQ query

When i use the results of a linq-to-xml query to populate a datagridview, i cannot edit the datagridview. i've tried setting the datagridview's readonly property to false and that doesn't help. I also added an event handler for cellBeginEdit and put a breakpoint there, but it doesn't get hit. Any idea what i'm doing wrong, or if this isn't possible?
public class MergeEntry
{
public string author { get; set; }
public string message { get; set; }
}
...
var query = from entry in xmlDoc.Descendants("entry")
select new MergeEntry
{
author = entry.Element("author").Value,
message = entry.Element("msg").Value,
}
var queryAsList = query.ToList();
myBindingSource.DataSource = queryAsList;
myDataGridView.DataSource = myBindingSource;

Yes, it is possible to bind to a list created from Linq-To-Xml. I tried to reproduce your problem. I did the following:
Created an empty WindForm project (VS 2008 and .Net 3.5)
Added a DataGridView to the Form.
Wired the CellBeginEdit and CellEndEdit.
Placed the following code in the Form's constructor
string testXML =
#"<p><entry>
<author>TestAuthor1</author>
<msg>TestMsg1</msg>
</entry></p>
";
XElement xmlDoc = XElement.Parse(testXML);
var query = from entry in xmlDoc.Descendants("entry")
select new MergeEntry
{
author = entry.Element("author").Value,
message = entry.Element("msg").Value,
}; //You were missing the ";" in your post, I am assuming that was a typo.
//I first binded to a List, that worked fine. I then changed it to use a BindingList
//to support two-way binding.
var queryAsList = new BindingList<MergeEntry>(query.ToList());
bindingSource1.DataSource = queryAsList;
dataGridView1.DataSource = bindingSource1;
When running the WinForm app, an editable grid was displayed and the CellBeginEdit and CellEndEdit events were fired when they should have been. Hopefully trying to reproduce using the above steps will help you locate the issue you are facing.

Since you're using ToList, your DataSource is actually a List<MergeEntry>, so the fact that it comes from a Linq query doesn't change anything. I suspect the ReadOnly property of the columns (not the DGV) is set to true... I see no other reason why the grid wouldn't be editable

This solution may not efficient but it works for me,
I moved all data (which is from LINQ) into a new collection and passed that new collection as datasource to gridview.
Now gridview allow us to edit cells.