I want my combobox to enable the autocomplete if what the user is typing is in the items list and if it doesn't exists, I want to include it in my list.
For example:
A ComboBox with these items: "Rock, Country, Jazz".
If the user starts typing "Ro..." the combobox autocomplete to 'Rock'. But if the user types "Blues", I want to add it to my items. So it would be like: "Rock, Country, Jazz, Blues".
How can I do that?
You can use AutoCompleteMode and AutoCompleteSource for auto complete.
comboBox1.AutoCompleteMode = AutoCompleteMode.Append;
comboBox1.AutoCompleteSource = AutoCompleteSource.ListItems;
or you can do this via Properties Panel in Visual Studio after selecting your ComboBox...
For adding new items to your ComboBox;
private void comboBox1_TextChanged(object sender, EventArgs e)
{
if (!comboBox1.Items.Contains(comboBox1.Text))
{
comboBox1.Items.Add(comboBox1.Text);
comboBox1.Items.RemoveAt(comboBox1.Items.Count - 2);
}
}
If I was doing this using MVVM, I would start with a ComboBox and modify it to suit.
You can get this almost for free if you use the built in ComboBox in DevExpress. Simply fill the dropdown list up with items that you want to auto-complete, then set the options for:
Auto dropdown (so when you start to type, it will automatically drop down a list of matches).
Filter list by match (i.e. the only items in the dropdown will be the ones that match what you have typed).
Match on partial (i.e. what you typed will filter the dropdown list, with a match anywhere, even in the centre).
If you wanted to get fancier, you could write a service that listens to what the user has currently typed in the box, then adjust the list of dropdown items to suit. Any items in the dropdown list that matches what the user types will automatically be displayed. I would use Reactive Extensions (RX) and Throttle to do this, see:
How to throttle event stream using RX?
The difference between Rx Throttle(...).ObserveOn(scheduler) and Throttle(..., scheduler).
Related
I've been programming some little project in Visual Studio using c# (.NET FRAMEWORK) and in some of my windows forms I want to show in different lisboxes the information about some object.
In my program I got a class named Client that has some Properties: an int called DNI (this is the one that identifies a Client), a string called Name and an int called Telephone. I want a form to show 3 different listboxes, each one with the list of elements of a collection of Client objects. The point is that a Client object has it's Properties showed in the same index of each listBox (to be said, reading horizontally you see the three values of the properties). I have implemented a button in top of each one that alphabetically sorts the elements of the listBox, but I would like to make a Binding between them so When you alphabetically sort one listbox, the other two sort their elements to match the new order of elements in the one alphabetically sorted.
I've been told the class DataBindingscan be used to do this. I've tried searching on the internet about it but achieved nothing and reading the documentation didn't help either, so I ended up posting it here. How can I use DataBindings to solve this? Any help or hint will be appreciated, thanks in advance.
What must I write to bind the indexes of them?
I recommended a datagridview; you seem to have tabular data that you want to show in a tabular fashion.. However, we'll demo all of it.
Easiest route:
Make a new winforms project
Add a DataSet type of file, open it, right click the design surface and choose Add .. DataTable
Name the table Client
Right click it and add column, call it DNI, use the props grid to make its type Int32
Add a string column Name
Add an int column Telephone
Save, switch to Form1 designer
Open Data Sources window (View menu, Other Windows)
Drag the Client node onto the form. A datagridview appears along with some stuff in the tray. Remove the navigator; it's not so useful in this context
Add 3 listboxes to the form
For each listbox:
Use the props grid to set its DataSource to the bindingsource
Set the DisplayMember to a different column - one DNI, the other Name and the third Telephone
That's it for now, run the app. Type some data in the datagridview. Note that when you sort by clicking the DGV header, the listboxes follow; this is because the sort instruction is being carried out by the bindingsource, and all controls bind through the bindingsource:
So that's thngs bound through a bindingsource to a strongly typed datatable, which is conceptually not really any different to what you have. The bit of work making the table and its columns in the design surface is the notional equivalent of making a class with properties. Indeed if you were to open the DataSetBlahBlah.Designer.cs file you'd find a class ClientRow with 3 properties DNI, Name, Telephone
You could change up everything you've made to be based on e.g. a List<Client> but your sorting life becomes slightly more awkward because a BindingSource doesn't understand how to sort it. As such you'd end up with something like:
//class property
private List<Client> Clients = new();
//in constructor
clientBindingSource.DataSource = Clients;
//in button that does sorting:
clientBindingSource.DataSource = Clients.OrderBy(c => c.name); //etc
Personally I'd leave it as a strongly typed datatable; for what you'd want out of a List<Client> a ClientDataTable collection of ClientRow are surface similar enough..
Clients.Where(c => c.Name == "John"); //how you might search a List<client>
ClientsDT.Where(c => c.Name == "John"); //how you might search a ClientDataTable
Clients.Add(new Client(){ DNI = 1, Name = "a", Telephone = 1 } ); //add to a List<Client>
ClientsDT.AddClientsRow(1, "a", 1); //how you might add to a ClientDataTable
etc
If you have already implemented a button for each, you've almost finished.
Every ListBox have to be bound with a List of Client, showing a specific property as DisplayMember.
The button of each ListBox can sort the List and refresh all of the ListBoxes.
If you want more information, please post some of your code.
I am creating a ComboBox array dynamically and the DataSource for all the ComboBox is a single integer list that contains some integers. But when I change a value say X in any one combo box then all other combo values get reset to value X.
So here is the situation:
All combo box controls are bound to a single list
When I change selected item of a combo box, selected item of all other combo box controls also change.
How can I stop these behavior?
Since you are binding all combo boxes to the same data source - a single list - they are using a single BindingManagerBase.
So when you choose an item from one of combo boxes, the current Position of the shared binding manager base changes and all combo boxes goes to that position of their shared data source.
To solve the problem you can bind them to different data source:
You can bind them to yourList.ToList() or any other list for example different BindingList<T>.
combo1.DataSource = yourList.ToList();
combo2.DataSource = yourList.ToList();
You can use different BindingSource for them and set your list as DataSource of BindingSource
combo1.DataSource = new BindingSource { DataSource= yourList};
combo2.DataSource = new BindingSource { DataSource= yourList};
Also as another option:
You can use different BindingContext for your combo boxes. This way even when you bind them to a single list, they are not sync anymore.
combo1.BindingContext = new BindingContext();
combo1.DataSource = yourList;
combo2.BindingContext = new BindingContext();
combo2.DataSource = yourList;
In fact all controls of the form use a shared BindingContext. When you bind 2 controls to a same data source, then they also use the same BindingManagerBase this way, when you for example move to next record, all controls move to next record an show value from bound property of next record. This is the same behavior that you are seeing from your combo boxes. Being sync for controls which are using the same BindingManagerBase is a desired behavior. Anyway sometimes we don't need such behavior. The post shares the reason and the solution.
I have a combobox binded to an observable collection through
cmbBladesTab1.ItemsSource = easyRunData.olstBlades;
that works fine.
I want the combobox to be binded to all that values plus one.
E.g.
easyRunData.olstBlades; contains "PL1", "PL2", "PL3", "PL4"
while cmbBladesTab1 contains "ALL BLADES", "PL1", "PL2", "PL3", "PL4"
--ADD all work has to be done from code-behind
Thanks for your help.
You could add a property, that adds the particular item to the list.
ObservableCollection<string> myCollection;
ObservableCollection<string> MyCollectionViewProp
{
get
{
var tempCollection = new ObservableCollection<string>(myCollection);
tempCollection.Add("Extra element");
return tempCollection;
}
}
Depending on the size of the collection and the number of times it is accessed, this is probably the programmatically simplest solution. If you need to access it often, the worse this solution gets, as it creates a new collection every time.
In this case you should probably listen to the CollectionChanged event and keep a separate redundant list.
Easiest way would be to add an extra item in the observable collection with some prefixed text / key.
That way, because it's in the collection, it will be visible in the combobox and when the user selects this item you can evaluate it to see if it's the added item or not.
A good example is indeed given as an answer on this question add an item to combobox before bind data from data base
I am struggling to figure out the correct control to use for a list of predefined jobs in the included form. I currently have a ListBoxControl in the Predefined Job Name group that lists all of the predefined jobs for a marine service shop (i.e. oil change, tune up, etc...). Then, based on the item (i.e. job name) that is selected in my ListBox, I need to display the items that correspond to that job. For example, if oil change is the selected job I need to show 4 quarts oil, 1 oil filter, labor, etc...and so on.
Currently, when I load the form data I have a DAO that retrieves all of my jobs from the database using LINQ to SQL. Then I iterate over the results and put the job names into the ListBox. The problem that I am having is that there is no tag for ListBox items like there is for ListView items. So each time the user selects another item in the ListBox, I have to perform another LINQ query to get the job from the database again so that I can display its' corresponding items. If I could use a ListView and hide the column header I could set the entire job on the tag so that each time the user selects a new item I would have access to the details without having to make another call to the database. Is there a way that I can hide the column header of a ListView without hiding the entire column?
You can set the HeaderStyle member of the ListView to None.
listView1.HeaderStyle = System.Windows.Forms.ColumnHeaderStyle.None;
Checkout the ListView HeaderStyle property. It has the following options:
None
Nonclickable
Clickable
From MSDN:
The HeaderStyle property allows you to specify whether the column headers are visible or, if they are visible, whether they will function as clickable buttons. If the HeaderStyle property is set to ColumnHeaderStyle.None, the column headers are not displayed, although the items and subitems of the ListView control are still arranged in columns
You can also create simple object like ListItem which has two poperties: Text (string) and Tag (object). Then implement ListItem.ToString() and you can use these in the ListBox as well.
You can also check out Better ListView Express component, which is free and allows displaying items in Details view without columns. The advantage over ListBox and ListView is a native look and many extra features.
Easy way is using the ColumnWidthChanging event
private void listViewExtended1_ColumnWidthChanging(object sender, ColumnWidthChangingEventArgs e)
{
if (e.ColumnIndex == 0)
{
e.Cancel = true;
e.NewWidth = listViewExtended1.Columns[e.ColumnIndex].Width;
}
}
I found that if you know for a fact you are not displaying the headers it may be best to set the HeaderStyle property to None, as Rajesh mentions above.
When setting in the .CS when screen initially loads the headers are displayed until screen is fully rendered.
I have a pretty simple form with a listbox, a text box, and two buttons.
The list box items are populated from a sql database table. The user may chose to select one or multiple items from the listbox.
The text box is used to write more details about the items in the listbox. One button can then be clicked to update another database table with these details.
I want to make it where if any items are selected from the listbox, those contents are automatically copied into the text box field on the fly as they are selected.
Is this possible?
I've been able to make this happen on the button click event - just not on the fly as they are selected. I want it to occur before the additional details are being sent to the database
I've also tried using several different listbox events, but have been unable to obtain the results I am looking for.
Any suggestions?
try this out
you will have to handle the SelectedIndexChanged event on the listbox.
here is an example with example controls.
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
textBox1.Text = "";
foreach (string nextitem in listBox1.SelectedItems)
{
textBox1.Text += nextitem + " ";
}
}
im not too sure HOW you want the text to appear in the textbox so that would be up to you in the foreach loop.
yes, the SelectedIndexChanged event fires on every selection change, and you can concatenate together the items in the listbox. But if you are talking the description that's not visible too, you need to store the description in each listboxitem tag property, and in your code retrieve the description from there.