I'm creating a form that will act as a master-detail editor. I have 2 controls on this form. One is basically a list of mater items and the other control is the details of the item. I'm trying to use a the same BindingSource object in both controls so that when a change is made on the master control, the detail control will get updated.
In my form I have:
EmployerCollection employerCollection = new EmployerCollection();
employerCollection.GetMulti(null, 0, new SortExpression(EmployerFields.Name | SortOperator.Ascending));
bsEmployers.DataSource = employerCollection;
masterControl.Init(bsEmployers);
detailControl.Init(bsEmpoyers);
In my masterControl I have:
public void Init(BindingSource bs)
{
bsEmployers = bs;
}
However for the life of me I can't get my master control to display the data in the binding source when I pass it in this way.
I can get binding to work only if I remove the bsEmployers = bs line and move the other logic as follows:
public void Init(BindingSource bs)
{
EmployerCollection employerCollection = new EmployerCollection();
employerCollection.GetMulti(null, 0, new SortExpression(EmployerFields.Name | SortOperator.Ascending));
bsEmployers.DataSource = employerCollection;
}
Does anyone have any idea what I can't pass the BindingSource object in to share it? I tried calling RefreshBindings in my control, but it did not seem to have any effect.
Thanks.
I don't think that the BindingSource was intended to be used that way. I would recommend passing the EmployerCollection value to the Init method and have each control create its own BindingSource using the EmployerCollection.
Related
I have a User Control that contains a combobox/drop down list. This user control is used multiple times and added dynamically to a panel. When I change the value of the combobox on one user control, it changes the rest? Does anyone know how to sort this?
So to clarify. When I change the value in the combobox of the top usercontrol (7002), it will change the second user controls combobox value to whatever I selected.
Thanks!
Code for adding the controls;
foreach (Common.UserDTO UDTO in BLL.User.GetAllUsers())
{
Admin_UserControls.UserBar UB = new Admin_UserControls.UserBar(UDTO);
UB.Location = new Point(0, int.Equals(pnlUserBlock.Controls.Count, 0) ? 0 : pnlUserBlock.Controls[pnlUserBlock.Controls.Count - 1].Bottom);
pnlUserBlock.Controls.Add(UB);
}
constructor/load events:
private Common.UserDTO UDTO;
public UserBar(Common.UserDTO UDTO)
{
InitializeComponent();
/* Store the passed in UserDTO */
this.UDTO = UDTO;
}
private void UserBar_Load(object sender, EventArgs e)
{
/* Setup the Drop down list */
cbRanks.DataSource = Common.Helper.GetRanksDT();
cbRanks.DisplayMember = "Rank";
cbRanks.ValueMember = "ID";
/* Setup the users */
lblUsername.Text = UDTO.Username;
cbRanks.SelectedValue = UDTO.RankID;
}
Put the above comment into an answer should others have the same issue in future.
Each instance of the UserControl that is created is bound to the same DataSet giving you this result.
Caused by the line:
cbRanks.DataSource = Common.Helper.GetRanksDT();
To resolve this simply declare a new instance each time the UserControl is created, see this post that discusses a few methods.
I have a C# Form that prints multiple instances of a User Control. Let's say that the form prints 5 instances of the User Control (Please see the link attached). How can I store/save the data inputted in all User Controls? Thanks
Here is the screenshot of the C# Form:
You'll have to store the User Controls when you instantiate them in a List or something.
You could have a class like this:
class SomeUC : UserControl
{
public SomeUC()
{
}
// A public method.
public string GetData()
{
return textBox1.Text;
}
}
Where textBox1 is the Name of a TextBox in your SomeUC
And then inside your main or something.
// Instantiate a List that will hold your UserControls, this has to be outside all methods
List<SomeUC> list = new List<SomeUC>();
// And now when you want to build your UCs
// Instantiate your UserControl
SomeUC uc1 = new SomeUC();
// Store your UserControl in a List or something (Can't help you with that)
list.Add(uc1);
Add as much as you want.
A List is not the only way you can do that, but since you don't know how many UserControls you're going to build beforehand, it makes since to use a List.
And then you can access them from the list by their index.
SomeUC uc1 = list[0];
string data = uc1.GetData();
This is an example of accessing one control (the TextBox) in your SomeUC. For other classes (such as the ComboBox) the interaction is different. Meaning you won't have a Text property in the ComboBox. You'll have to figure out things like that on youself. A little research is what it takes. You can always come back if you couldn't find a solution for something.
You can create a property like this for each item in user control.
public string DG
{
get
{
return txtDG.Text;
}
set
{
txtDG.Text = value;
}
}
Then you can access the control value by using following line in your form.
supposed you have created a usercontrol MyControl and you have placed some object of this control in FlowLayoutPenal (pnlFLP).
To get value from control
string DG = ((MyControl)pnlFLP.Controls[0]).DG;
To set value in control
((MyControl)pnlFLP.Controls[0]).DG = "1";
Try this code for accessing user control in the page
Dim txtName As TextBox = TryCast(UserControlName.FindControl("txtName"), TextBox)
I have tow form,ListFrom, and DetailForm
In the ListForm I have a devexpress grid and some button(add, delete, edit)
In the DetailForm I have some textboxes and some button(save,delete,next,previous)
well I have to senario
1 - I open the ListForm and I click on a product to modify it a got the DetailForm opened, I make some modification and I save,then i should have my grid in the ListForm refreshed with the new value.for this I have this code
In the ListFrom
FrmProduit frm = new FrmProduit(monProduit.Id) { MdiParent = this.MdiParent};
frm.updateDataInGridView += new System.Action(refereshGridView);
frm.Show();
in the detailform
if (updateDataInGridView != null)
updateDataInGridView();
well in this scenario everything is OK
second scenario
If I open the detailFrom,and after that I open the listForm, I make some change in the detailFrom and I click save updateDataInGridView in this case is null and then the grid is not refreshed
anyone have suggestion?
I would create a shared BindingSource that both forms would use to show data. If any item is changed in BindingSource it takes care to notify all controls bind to it and so it would refresh grid automatically.
Second approach is to make refereshGridView method public and in DetailForm on save click do this:
var lists = Application.OpenForms.OfType<Form>().Where(x => x.GetType() == typeof(ListFrom));
foreach (var listform in lists)
{
listform.refereshGridView();
}
I did not use FirstOrDefault as maybe there is more than one listform opened.
EDIT about Binding Source
Here is quite good tutorial so please take a look.
Below is a fast-written far from best example of stretch I did:
internal static class DataSources
{
private static BindingSource bs;
public static BindingSource CerateDataSource(List<object> yourObjects)
{
bs = new BindingSource();
bs.DataSource = yourObjects;
}
public static BindingSource GetDataSource()
{
return bs;
}
public static void Reset()
{
bs.ResetBindings(false);
}
}
and then in your listview
dataGridView1.DataSource = DataSources.GetData();
and in detailsview where you are editing one of the objects from BindingSource on save you would have to call: DataSources.Reset();. This is just a markup, but hopefully you get the idea :).
You must always be sure you are referring to the current instance of detailform, thus declare on your listForm
detailform obj = (detailform)Application.OpenForms["detailform"];
And every time you call detailform from listForm do it by obj e.g:
obj.Show()
int[] arr = int[100];
listBox1.DataSource = arr;
void ComboBox1SelectedIndexChanged(object sender, EventArgs e)
{
.....//some processes
listBox1.DataSource = null;
listBox1.DataSource = arr;
}
is not working,
also,
listBox1.Refresh(); is not working,
also,
listBox1.Update(); is not working,
i know i can use BindingList<T> but i have to work with only array.
can you help me how can i refresh listbox?
my first answer on stack exchange here.
C# .Net 4.0:
listBox1.DataSource = null;
listBox1.DataSource = names;
I noticed that setting the datasource for the first time, it refreshes.
When it's set, and you try set it to the same one again, it doesn't update.
So I made it null, set it to the same one, and it displayed correctly for me with this issue.
ListBox only updates its shown content when the object that is binded on dataSource notifys it own changes. the BindingSource object has an event called DataSourceChanged. when the Source is changed to a different object the Listbox will update itself.
Same thing when you bind a List. Nothing will happen if you change the List, because the List doesn't notify that it has been changed. There is a Simple solution for this Problem: use BindingList
http://msdn.microsoft.com/de-de/library/ms132679%28v=vs.110%29.aspx
the BindingList has the ListChanged Event is called every time when the List is changed (obviously). So the DataBindings of Windows.Form objects use events like ListChanged to update themselves. A simple List doesn't support this event.
SO if you want to work with a lot of Data Bindings you should know about:
http://msdn.microsoft.com/de-de/library/system.componentmodel.inotifypropertychanged%28v=vs.110%29.aspx
Managed to do just with
FirstListBox.DataContext = null;
FirstListBox.DataContext = App.ViewModel;
Simply loses link and get all the data back to it.
I inherited ListBox and added a public method calling RefreshItems() which does what we want. Already implemented and all. I dont know why they didnt put in a public method.
The problem might come from the ListBox SelectionMode.
For a reason that I don't know, the databinding does not work when SelectionMode is SelectionMode.None.
A workaround could be:
listBox.SelectionMode = SelectionMode.MultiExtended;
listBox.DataSource = myDatasource;
listBox.SelectionMode = SelectionMode.None;
Hope it helps.
well, without binding I only managed with:
this.Hide();
this.Show();
it redraws everything...
try the following
listBox1.DataBind()
Use BeginUpdate and EndUpdate, that should solve it.
No need to set the data source twice
listBox1.BeginUpdate();
listBox1.DataSource = myList;
listBox1.EndUpdate();
Windows forms to see changes especially on Listbox and other controls before load is finished is tricky.
To see data as its loaded use invalidate(); then Update();
Quick Answer
BindingSource bs = new BindingSource();
bs.DataSource = arr;
listbox1.DataSource = bs;
arr[0] = 100; //Do some value change
bs.ResetBindings(false); //Refresh the listbox
Explanation
As stated by Microsoft:
The BindingSource component serves two purposes. First, it provides a layer of indirection when binding the controls on a form to data. This is accomplished by binding the BindingSource component to your data source, and then binding the controls on your form to the BindingSource component. All further interaction with the data, including navigating, sorting, filtering, and updating, is accomplished with calls to the BindingSource component.
So, if you have multiple Controls binded with same data which changes frequently, it is suggested to use BindingSource rather than setting DataSource property of the Controls directly to an Array or List etc.
Moreover, with decompiling ListBox class which is inherited from ListControl in .net 4.6.2, the setter of property DataSource is:
if ((value != null) && (!(value is IList) && !(value is IListSource)))
{
throw new ArgumentException(System.Windows.Forms.SR.GetString("BadDataSourceForComplexBinding"));
}
if (this.dataSource != value)
{
try
{
this.SetDataConnection(value, this.displayMember, false);
}
catch
{
this.DisplayMember = "";
}
if (value == null)
{
this.DisplayMember = "";
}
}
We can see if the value is null the DisplayMember property will automaticly be set to empty. And when you reset a value, several initialization will be performed in SetDataConnection method which takes extra cost.
In contrast, calling BingdingSource.ResetBindings only fires an event:
public void ResetBindings(bool metadataChanged)
{
if (metadataChanged)
{
this.OnListChanged(new ListChangedEventArgs(ListChangedType.PropertyDescriptorChanged, null));
}
this.OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
}
Although I didn't find the handler in ListBox but I guess there should be less side effects. So I think the highest voted answer is not the best solution.
I'm trying to bind a collection to a DataGridView. As it turns out it's impossible for the user to edit anything in this DataGridView although EditMode is set to EditOnKeystrokeOrF2.
Here is the simplified code:
public Supplies()
{
InitializeComponent();
List<string> l = new <string>();
l.Add("hello");
this.SuppliesDataGridView.DataSource = l;
}
It also doesn't work when I change the collection type to SortableBindingList, Dictionary or even use a BindingSource.
What can be wrong here?
For me the following method works as expected:
Open your form (usercontrol, etc.) with the designer
Add a BindingSource to your form
Select the BindingSource in your form and open the properties page
Select the DataSource property and click on the down arrow
Click on Add project data source
Select Object
Select the object type you wish to handle
This should be the type that will be handled by your collection, not the CustomCollection itself!
Show the available data sources by selecting from the MenuBar Data - Show Data Sources
Drag and Drop your ItemType from the DatasSources on your form
Go into the code of your form and bind your CustomCollection to the BindingSource
var cc = new CustomCollection();
bindingSource1.DataSource = cc;
Remarks:
The DataGridView is just the last part in your chain to (dis)allow changing, adding and removing objects from your list (or CustomCollection). There is also a property AllowNew within the BindingSource and the ICollection interface has a property IsReadOnly which must be set to false to allow editing. Last but not least, the properties of your class within the collection must have a public setter method to allow changing of a value.
Try this:
public class CustomCollection { public string Value { get; set; } }
public Supplies()
{
InitializeComponent();
List<CustomCollection> l = new List<CustomCollection> { new CustomCollection { Value = "hello" } };
this.SuppliesDataGridView.DataSource = l;
}
Once you've set the DataSource property you'll then want to fire off the DataBind() method.
this.SuppliesDataGridView.DataSource = l;
this.SuppliesDataGridView.DataBind();
UPDATE:
As you rightly pointed out in the comments, the DataBind() method doesn't exist for this control.
This link might provide some helpful information: http://msdn.microsoft.com/en-us/library/fbk67b6z%28v=VS.90%29.aspx