I have problem with my combobox. When I select an item from my combobox it does not go to my addSelectionListener except for the first time when the program starts. How to make it take the user's selection.
here is the code:
private Tirage tirage;
private ComboBox<Tirage> comboBoxTir2;
List<Tirage> tirages;
tirages = tirageService.findByTirageFutur(produit.getId(), envService.getDateLogique());
comboBoxTir2 = new ComboBox<>();
comboBoxTir2.setItems(tirages);
comboBoxTir2.setItemCaptionGenerator(Tirage::getNoTirage);
comboBoxTir2.addSelectionListener(event -> {
tirage = event.getValue();
});
sectionVerticalPage.addComponent(comboBoxTir2);
Can anyone help me ?
Related
Updated 10 Nov 2022
I have the following code in a Winforms program:
void CreateCheckBoxes(Control parentControl, int left, int top, int lineSpace)
{
List<string> listVariables = new List<string>() { "AllowColumnReorder", "CaptureFocusClick", "ColScaleMode", "ColumnTracking", "RowTracking", "EnsureVisible", "FullRowSelect", "GridLines", "HideSelection", "HoverSelection", "IsFocused", "LabelEdit", "MultiSelect", "Scrollable", "VisualStyles" };
foreach (string varName in listVariables)
{
CheckBox ctlTemp = new CheckBox { Name = "chk" + varName, Text = varName, Top = top, Left = left };
parentControl.Controls.Add(ctlTemp);
top += lineSpace;
}
chkAllowColumnReorder.CheckedChanged += new EventHandler(chkAllowColumnReorder_CheckedChanged);
// The name 'chkAllowColumnReorder' does not exist in the current context
}
It works to the extent that I can create as many CheckBoxes as I like based on the length of listVariables. However, I want the name of the CheckedChanged event handler to be based on the name of the control.
As well as my original question I now find I cannot refer to the CheckBox by the name provided in { Name = "chk" + varName, in the debugger a watch on "Name" returns the name of the form. I have not used this form of constructor before and am struggling to find any documentation on it. Can anybody help on this before I try to move on again please?
Is there a way to do this?
The code itself is produced by a small program where I just past in the names of variables from the main program and it produces the above, and all the vent handlers, which is an enormous time saver.
jimi - I've posted this as an answer as it's too long for a comment.
I ended up with:
Dictionary<string, Action<CheckBox>> m_Actions = new Dictionary<string, Action<CheckBox>>();
then loop through:
m_Actions.Add("chkAllowColumnReorder", (c) => containerListView1.AllowColumnReorder = c.Checked); etc.
and then:
void chkTemp_CheckedChanged(object sender, EventArgs e)
{
CheckBox chkTemp = ((CheckBox)sender);
m_Actions[chkTemp.Name](chkTemp);
}
This is completely new to me and I'm still not sure how (or why) it works but thank you very much for telling me about it - I can now paste variables in to my app's form and produce all the code to add controls to the app I need to test.
I did it because my heart sank at the thought of adding heaps of CheckBoxes to an app to test an ExtendeListView, in the end writing this to produce the code was much more interesting than the testing!
Afternoon,
I have a search button which searches the list of the users is either by IDnumber,Username or department.
I have 2 list view which the users clicks and it load the selected user to the second list view. now the problem is after u clicked users from listview1 and u went to type ID,Username or select department and click search...It clears all the users you selected and bring new users u where searching.
I want to be able to select the users and be able to search without losing my current selected users from the listview
my code ;
//search button
private void Searchbutton_Click(object sender, EventArgs e)
{
try
{
listView1.Items.Clear();
string sID = string.IsNullOrEmpty(txtUserID.Text) ? null : txtUserID.Text;
string sDepartment;
if (cboDepartment.SelectedItem != null)
{
sDepartment = cboDepartment.SelectedItem.ToString();
}
else
{
sDepartment = "";
}
oConnection = new SqlConnection(_connectionString);
oCommand = new SqlCommand(#"Select us.sFieldValue5, u.sUserName, d.sName, TB_USER_CUSTOMINFO.sFieldValue2
From TB_USER u(nolock)
left join [TB_USER_CUSTOMINFO] us(nolock) on us.nUserIdn = u.nUserIdn
left join TB_USER_CUSTOMINFO on u.nUserIdn = TB_USER_CUSTOMINFO.nUserIdn
left join TB_USER_DEPT d(nolock) on d.nDepartmentIdn = u.nDepartmentIdn
where u.sUserName like '%'+ISNULL(#UserName,u.sUserName)+'%'
and us.sFieldValue5 = isnull(#IDNumber,us.sFieldValue5)
and d.sDepartment like '%'+isnull(#Department,d.sDepartment)+'%'", oConnection);
oCommand.Parameters.AddWithValue("UserName", string.IsNullOrEmpty(txtUsername.Text) ? DBNull.Value : (object)txtUsername.Text);
oCommand.Parameters.AddWithValue("IDNumber", string.IsNullOrEmpty(txtUserID.Text) ? DBNull.Value : (object)txtUserID.Text);
oCommand.Parameters.AddWithValue("Department", string.IsNullOrEmpty(sDepartment) ? DBNull.Value : (object)sDepartment);
oConnection.Open();
oDataset = new System.Data.DataSet();
SqlDataReader oReader = oCommand.ExecuteReader();
while (oReader.Read())
{
ListViewItem item1 = new ListViewItem(oReader[1].ToString());
item1.SubItems.Add(oReader[2].ToString());
item1.SubItems.Add(oReader[3].ToString());
item1.SubItems.Add(oReader[0].ToString());
listView1.Items.AddRange(new ListViewItem[] {item1});
}
oReader.Close();
oConnection.Close();
}
//selected users
private void listView1_ItemChecked(object sender, ItemCheckedEventArgs e)
{
if (e.Item.Checked == true)
{
ListViewItem l = listView1.Items[e.Item.Index];
int i = l.SubItems.Count;
string sValue1 = l.SubItems[1].Text;
string sValue2 = l.SubItems[2].Text;
string sValue3 = l.SubItems[3].Text;
ListViewItem item1 = new ListViewItem(l.SubItems[0].Text.ToString());
item1.SubItems.Add(sValue3);
item1.SubItems.Add(sValue2);
item1.SubItems.Add(sValue1);
listView2.Items.AddRange(new ListViewItem[] { (ListViewItem)l.Clone() });
}
else if (e.Item.Checked == false)
{
ListViewItem l = listView1.Items[e.Item.Index];
foreach (ListViewItem i in listView2.Items)
{
if (i.SubItems[0].Text == l.SubItems[0].Text.ToString())
{
listView2.Items.Remove(i);
}
}
}
}
ListView remember which ListViewItems were checked. As soon as you say Items.Clear(), all that knowledge is lost.
To solve your problem, you will need to remember which users were checked, do your refresh, then go through and mark each user as checked again.
To do those steps, you really need to separate your model from your view. Create a User model object to hold the actual data, then populate your ListView with data from your model. When the user does another search, update or refresh your model objects, then rebuild your view.
Doing this model/view separation is a little more work up front, but future generations of maintenance programmers will bless your name.
BTW, ObjectListView -- an open source wrapper around a .NET ListView -- makes creating a fully functional ListView from a list of model objects trivially easy.
I want to have a drop down list with 12 choices.
I found that ComboBox is what I need (if there is a better control kindly tell me).
I dragged and drop a combo box into a panel using VS2012 and then clicked on the left arrow that appears on the combo box. The following wizard shows:
As you can see, I am just able to type the name of the choice but not the value of it.
My question is how to get the value of these choices?
What I have tried
I built an array with the same length as the choices, so when the user selects any choice, I get the position of that choice and get the value from that array.
Is there a better way?
You need to use a datatable and then select the value from that.
eg)
DataTable dt = new DataTable();
dt.Columns.Add("ID", typeof(int));
dt.Columns.Add("Description", typeof(string));
dt.Load(reader);
//Setting Values
combobox.ValueMember = "ID";
combobox.DisplayMember = "Description";
combobox.SelectedValue = "ID";
combobox.DataSource = dt;
You can then populate your datatable using:
dt.Rows.Add("1","ComboxDisplay");
Here, the DisplayMember(The dropdown list items) are the Descriptions and the Value is the ID.
You need to include a 'SelectedIndexChanged' Event on your combobox (If using VS then double click the control in Design Mode) to get the new values. Something like:
private void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
int ID = Combobox.ValueMember;
string Description = ComboBox.DisplayMember.ToString();
}
You can then use the variables in the rest of your code.
You cannot use the wizard to store values and text. To store DisplayText/Value pair the combobox needs to be connected to some data.
public class ComboboxItem
{
public string DisplayText { get; set; }
public int Value { get; set; }
}
There are two properties on the combobox - DisplayMember and ValueMember. We use these to tell the combobox that - show whats in DisplayMember and the actual value is in ValueMember.
private void DataBind()
{
comboBox1.DisplayMember = "DisplayText";
comboBox1.ValueMember = "Value";
ComboboxItem item = new ComboboxItem();
item.DisplayText = "Item1";
item.Value = 1;
comboBox1.Items.Add(item);
}
To get the value -
int selectedValue = (int)comboBox1.SelectedValue;
I've read all the similiar posts about this darn control (DataGridViewComboBoxCell) and setting it's value programmatically but implementing all the suggestions hasn't worked. I could probably change the UI to get around this problem but I don't like to be beat!
private void PopulateAreaForRoleAssociation()
{
// If businessRoleList is null then no data has been bound to the dgv so return
if (businessRoleList == null)
return;
// Ensure businessArea repository is instantiated
if (businessAreaRepository == null)
businessAreaRepository = new BusinessAreaRespository();
// Get a reference to the combobox column of the dgv
DataGridViewComboBoxColumn comboBoxBusinessAreaColumn = (DataGridViewComboBoxColumn)dgvBusinessRole.Columns["BusinessArea"];
// Set Datasource properties to fill combobox
comboBoxBusinessAreaColumn.DisplayMember = "Name";
comboBoxBusinessAreaColumn.ValueMember = "Id";
comboBoxBusinessAreaColumn.ValueType = typeof(Guid);
// Fill combobox with businessarea objects from list out of repository
comboBoxBusinessAreaColumn.DataSource = businessAreaRepository.GetAll();
// loop through the businessRoles list which the dgv is bound to and get out each dgv row based upon the current id in the loop
businessRoleList.Cast<BusinessRole>().ToList().ForEach(delegate(BusinessRole currentRole)
{
DataGridViewRow currentRowForRole = dgvBusinessRole.Rows.Cast<DataGridViewRow>().ToList().Find(row => ((BusinessRole)row.DataBoundItem).Id == currentRole.Id);
// Get a reference to the comboBox cell in the current row
DataGridViewComboBoxCell comboBoxCell = (DataGridViewComboBoxCell)currentRowForRole.Cells[2];
// Not sure if this is necessary since these properties should be inherited from the combobox column properties
comboBoxCell.DisplayMember = "Name";
comboBoxCell.ValueMember = "Id";
comboBoxCell.ValueType = typeof(Guid);
// Get the business area for the current business role
BusinessArea currentAreaForRole = businessAreaRepository.FetchByRoleId(currentRole.Id);
// if the role has an associated area then set the value of the cell to be the appropriate item in the combobox
// and update the cell value
if (currentAreaForRole != null)
{
foreach (BusinessArea area in comboBoxCell.Items)
{
if (currentAreaForRole.Id == area.Id)
{
comboBoxCell.Value = area.Id;
dgvBusinessRole.UpdateCellValue(2, comboBoxCell.RowIndex);
}
}
}
});
}
The dgv is first bound to a binding list holding BusinessRole objects, then the combobox column is bound to a basic list of BusinessArea objects that come out of a repository class. I then loop through the bindinglist and pull out the row of the dgv that is bound to the current item in the bindinglist loop.
With that row I make a database call to see if the BusinessRole entity is associated with a BusinessArea entity. If it is then I want to select the item in the combobox column that holds the BusinessAreas.
The problem is that when the grid is loaded, all the data is there and the comboboxes are populated with a list of available areas, however any values that are set are not displayed. The code that sets the value is definately getting hit and the value I am setting definately exists in the list.
There are no data errors, nothing. It's just refusing to update the UI with the value I programmatically set.
Any help would be greatly appreciated as always.
Thanks
This code works for my first combo box I have in my row with the following code, but I try it with the next one in the row and it doesn't work. I could use the help with the rest I have 3 more to do. I do set the combo boxes on a second form from this form with the same code as is on the last line of the try block but using the cell information instead of the dataset
try
{
string strQuery = "select fundCode from vwDefaultItems where IncomeType = '" + stIncome + "'";
SqlDataAdapter daDefault = new SqlDataAdapter(strQuery, conn);
DataSet dsDefault = new DataSet();
daDefault.Fill(dsDefault);
strDefFund = dsDefault.Tables[0].Rows[0].ItemArray[0].ToString();
dgvCheckEntry.Rows[curRow].Cells[7].Value = dsDefault.Tables[0].Rows[0].ItemArray[0].ToString();
}
catch (Exception eq)
{
}
This really seems like a bug to me, but perhaps some databinding gurus can enlighten me? (My WinForms databinding knowledge is quite limited.)
I have a ComboBox bound to a sorted DataView. When the properties of the items in the DataView change such that items are resorted, the SelectedItem in my ComboBox does not keep in-sync. It seems to point to someplace completely random. Is this a bug, or am I missing something in my databinding?
Here is a sample application that reproduces the problem. All you need is a Button and a ComboBox:
public partial class Form1 : Form
{
private DataTable myData;
public Form1()
{
this.InitializeComponent();
this.myData = new DataTable();
this.myData.Columns.Add("ID", typeof(int));
this.myData.Columns.Add("Name", typeof(string));
this.myData.Columns.Add("LastModified", typeof(DateTime));
this.myData.Rows.Add(1, "first", DateTime.Now.AddMinutes(-2));
this.myData.Rows.Add(2, "second", DateTime.Now.AddMinutes(-1));
this.myData.Rows.Add(3, "third", DateTime.Now);
this.myData.DefaultView.Sort = "LastModified DESC";
this.comboBox1.DataSource = this.myData.DefaultView;
this.comboBox1.ValueMember = "ID";
this.comboBox1.DisplayMember = "Name";
}
private void saveStuffButton_Click(object sender, EventArgs e)
{
DataRowView preUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem;
// OUTPUT: SelectedIndex = 0; SelectedItem.Name = third
Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, preUpdateSelectedItem["Name"]));
this.myData.Rows[0]["LastModified"] = DateTime.Now;
DataRowView postUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem;
// OUTPUT: SelectedIndex = 2; SelectedItem.Name = second
Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, postUpdateSelectedItem["Name"]));
// FAIL!
Debug.Assert(object.ReferenceEquals(preUpdateSelectedItem, postUpdateSelectedItem));
}
}
To clarify:
I understand how I would fix the simple application above--I only included that to demonstrate the problem. My concern is how to fix it when the updates to the underlying data rows could be happening anywhere (on another form, perhaps.)
I would really like to still receive updates, inserts, deletes, etc. to my data source. I have tried just binding to an array of DataRows severed from the DataTable, but this causes additional headaches.
Just add a BindingContext to the ComboBox :
this.comboBox1.DataSource = this.myData.DefaultView;
this.comboBox1.BindingContext = new BindingContext();
this.comboBox1.ValueMember = "ID";
this.comboBox1.DisplayMember = "Name";
By the way, try not keeping auto-generated names for your widgets (comboBox1, ...), it is dirty. :-P
The only promising solution I see at this time is to bind the combo box to a detached data source and then update it every time the "real" DataView changes. Here is what I have so far. Seems to be working, but (1) it's a total hack, and (2) it will not scale well at all.
In form declaration:
private DataView shadowView;
In form initialization:
this.comboBox1.DisplayMember = "Value";
this.comboBox1.ValueMember = "Key";
this.shadowView = new DataView(GlobalData.TheGlobalTable, null, "LastModified DESC", DataViewRowState.CurrentRows);
this.shadowView.ListChanged += new ListChangedEventHandler(shadowView_ListChanged);
this.ResetComboBoxDataSource(null);
And then the hack:
private void shadowView_ListChanged(object sender, ListChangedEventArgs e)
{
this.ResetComboBoxDataSource((int)this.comboBox1.SelectedValue);
}
private void ResetComboBoxDataSource(int? selectedId)
{
int selectedIndex = 0;
var detached = new KeyValuePair<int, string>[this.shadowView.Count];
for (int i = 0; i < this.shadowView.Count; i++)
{
int id = (int)this.shadowView[i]["ID"];
detached[i] = new KeyValuePair<int, string>(id, (string)this.shadowView[i]["Name"]);
if (id == selectedId)
{
selectedIndex = i;
}
}
this.comboBox1.DataSource = detached;
this.comboBox1.SelectedIndex = selectedIndex;
}
Must detach event handler in Dispose:
this.shadowView.ListChanged -= new ListChangedEventHandler(shadowView_ListChanged);
Your example sorts the data on the column it updates. When the update occurs, the order of the rows changes. The combobox is using the index to keep track of it's selected items, so when the items are sorted, the index is pointing to a different row. You'll need to capture the value of comboxBox1.SelectedItem before updating the row, and set it back once the update is complete:
DataRowView selected = (DataRowView)this.comboBox1.SelectedItem;
this.myData.Rows[0]["LastModified"] = DateTime.Now;
this.comboBox1.SelectedItem = selected;
From an architecture perspective, the SelectedItem must be cleared when rebinding the DataSource because the DataBinder don't know if your SelectedItem will persist or not.
From a functional perspective, the DataBinder may not be able to ensure that your SelectedItem from you old DataSource is the same in your new DataSource (it can be a different DataSource with the same SelectedItem ID).
Its more an application feature or a custom control feature than a generic databinding process.
IMHO, you have theses choices if you want to keep the SelectedItem on rebind :
Create a reusable custom control / custom DataBinder with a persistance option which try to set the SelectedItem with all your data validation (using a DataSource / item identification to ensure the item validity)
Persist it specifically on your Form using the Form/Application context (like ViewState for ASP.NET).
Some controls on the .NET market are helping you by rebinding (including selections) the control from their own persisted DataSource if the DataSource is not changed and DataBind not recalled. That's the best pratice.