When setting the source of an items control (ComboBox, for example), is it possible to have the SelectedValue property be different than the text that is displayed. I have a ComboBox that I want to display only the time portion of a DateTime, and have the value of each item be the DateTime object itself.
Thanks!
The combobox has an ItemStringFormat property that dictates how items are displayed in the dropdown and textbox parts of the control.
In the case of this example from the MSDN the SelectedValue will be a datetime objects, while the control itself will display the formatted strings.
See here for how to create the format string that will work for your problem. (Something like "HH:mm:ss" I'd guess)
Related
I am trying to implement a ComboBox with a calendar as its item. When the user selects a date on the calendar, this date becomes the ComboBox value/text. problem is when I click outside the ComboBox to close or the ComboBox goes unselected, the value then becomes "System.Windows.Controls.ComboBoxItem".
How do I keep the ComboBox value to the ShortDate string value even after the ComboBox loses focus?
here's my xaml
<ComboBox x:Name="datecombo" IsEditable="True" IsReadOnly="True" SelectedValue="{Binding SelectedDates}">
<ComboBoxItem>
<controls:Calendar x:Name="DropCalendar" SelectedDatesChanged="DropCalendar_SelectedDatesChanged CalendarSelectionMode="SingleRange"/>
</ComboBoxItem></ComboBox>
In the code behind I have a viewmodel that contains the property SelectedDates (bound to the selectedvalue attribute) which is set when the selected dates on the calendar change. This in turn sets the ComboBox value to the short date string of the selected date.
**edit: I think I need to use a Calendar because I want to be able to select a range of dates. I know this can also be possible to do with two DatePickers(one is for the start and the other for the end date) but I think doing this(Calendar on a ComboBox) would better fit with the UI's aesthetic, i guess. :D
I am now using a plain DataGridView component to display data with my own implementation of IBindingSource interface. The columns are binded to properties.
Now I am trying to compare the current "display value" in the grid (i.e. the actual previous value) and the latest value in the IBindingSource to determine background of the cell. Is it correct to compare the Value on the event with the value like Grid.Rows[rowIndex].Cells[columnIndex] ? Or is there any other way to do this?
Thanks in advance.
I have a form with two data-bound text boxes, one data-bound DateTimePicker and a BindingNavigator. I bind these components at run-time to the relevant data sources (the 'Text' and 'Value' of the Text Boxes and DateTimePicker respectfully are bound the relevant fields in a data set). All the components display the present records correctly. Normally, when one clicks the "Add New Item" button on the navigator, all the Text Boxes will clear in preparation for the new entry. However, I have the problem that this does not occur when the DateTimePicker is bound, and furthermore any attempts to update the datasets do not occur correctly. If I neglect to bind the DateTimePicker then all works as expected. What is the cause of this behaviour and is there a way around it?
The DateTimePicker doesn't support binding to nullable data. When you add a new row, the value for that field will be DBNull.Value by default and that cannot be converted successfully to a value that can be assigned to the Value property of the DateTimePicker, which is type DateTime. You need to either extend the DateTimePicker and add a new property that supports both DateTime values and DBNull objects and bind that or else set the DefaultValue property of your DataColumn so that there will always be a DateTime to display in the DateTimePicker.
This problem was resolved for my scenario by simply controlling the addrow method of the binding source based on this site: http://www.vbforums.com/showthread.php?645401-RESOLVED-datetimepicker-with-binding-source
Add a new button on the binding navigator (to use as your 'Add') and remove the old one.
Connect to the click event and set the datetime of the new row being added:
DataRowView row = (DataRowView)bs_.AddNew();
row["dbDateTime"] = DateTime.Now;
where dbDateTime is your database field.
Although you may have to add some more code to the click event, such as moving to the newly added row on the datagrid, this option was by far the easiest to implement.
I'm working on a GUI that allows the user to manipulate xml files. I display the xml file in a datagridview organized neatly by columns through xml elements. I allow the user to add columns as an extention on my project. The column gets added to the dataset table, then updated to the datagridveiew that I use to display the xml file in. I've included the ability for the user to add a combobox column to select choices instead of entering them in constantly like.. true or false. However, that is where the problem lies. Saving a normal column was easy. The combobox column is being a pain.
I have a "save combobox column" to have it updated to the xml and a "save" button to save in a destination of the user's choice.
I've done some research and it seems like the combobox class has such a feature to gain access to the selecteditem in the combobox put in by the user.
Where we have:
ComboBox box = new ComboBox();
box.SelectedItem;
I tried applying this to the combobox column class but it does not have such a function. Thus, I cannot figure out how to directly obtain the value of the user's selected item. I tried experimenting with comboboxcell's as well, but that didn't lead me anywhere either. Both those classes I played around with do not have a... "selected item" function and even google does not have a solution for me. =( I've also tried using the cell.value, but it is "null" for some reason. Even when the user selects an item in the box, it doesn't get saved into the cell's value.
TLDR:
My question in short is, how, if possible, do you gain access to the comboboxcolumn cell's selected item? Additionally, how would you then ensure that the item value is saved in the cell?
Thanks in advance. I'm using .NET 3.5 SP1, through Visual Studio 2008 C#.
Sincerely,
tf.rz
The Control in a DataGridView is not a ComboBox, it is a DataGridViewComboBox and has different properties and methods. From MSDN
Unlike the ComboBox control, the DataGridViewComboBoxCell does not have SelectedIndex and SelectedValue properties. Instead, selecting a value from a drop-down list sets the cell Value property.
However, you mentioned that the Cell.Value is null for you. Well there may be another step you are missing according to the following article (How to: Access Objects in a Windows Forms DataGridViewComboBoxCell Drop-Down List).
You must set the DataGridViewComboBoxColumn.ValueMember or DataGridViewComboBoxCell.ValueMember property to the name of a property on your business object. When the user makes a selection, the indicated property of the business object sets the cell Value property.
If we have bound a datagridcomboboxcell with a different DisplayMember and ValueMember, like so:
dgcombocell.DisplayMember = "Name";
dgcombocell.ValueMember = "Id";
dgcombocell.DataSource = dataset1.Tables[0];
Then for getting SelectedText, and SelectedValue, we can write this code:
string SelectedText = Convert.ToString((DataGridView1.Rows[0].Cells["dgcombocell"] as DataGridViewComboBoxCell).FormattedValue.ToString());
int SelectedVal = Convert.ToInt32(DataGridView1.Rows[0].Cells["dgcombocell"].Value);
I hope it solves your problem.
Use this to get or set selected value:
object selectedValue = currentRow.Cells["comboboxColumnName"].Value
Don't forget to set DisplayMember and ValueMember for your DataGridViewComboBoxColumn
This is how it is done
DataGridViewComboBoxCell comboCell = (DataGridViewComboBoxCell)dgv.Rows[0].Cells[1];
MessageBox.Show(""+comboCell.Items.IndexOf(comboCell.Value));
A .Net combox is actually a composite control made up of a textbox and a dropdownlist. Use box.Text to get the currently displayed information.
EDIT: The row or the cell should have a .FindControl() method. You'll need to do something like:
Combobox box = (Combobox)(row.FindControl("[combobox ID]"));
string val = box.Text;
Basically, you're finding the control within its container (row or cell), then casting the control found as a combobox, then accessing its .Text property.
I use this:
private int GetDataGridViewComboBoxCellSelectedIndex(DataGridViewCell d)
{
return ((DataGridViewComboBoxCell)d).Items.IndexOf(d.Value);
}
Edit 1
I believe my problem stems from the following. The function that fills the dropdown portion sets the Display Member to the CountyName. Then when I try and set the SelectedText or EditValue, as has been suggested, that function only returns the CountyID which it try's to match to something in the DropDown list DisplayMember. I need it to match it to something in the ValueMember list.
Using the following I got it to work but it is a HACK and I'd greatly appreciate finding a real solution.
lkuResidenceCounty.ItemIndex = Convert.ToInt32(row["ResidencyCountyID"].ToString());
Original Post
I have a lookup box(DevExpress) on a member form that I fill the possible values in from the DB with this code -->
lkuResidenceCounty.Properties.DataSource = ConnectBLL.BLL.Person.CountyList();
lkuResidenceCounty.Properties.PopulateColumns();
lkuResidenceCounty.Properties.DisplayMember = "CountyName";
lkuResidenceCounty.Properties.ValueMember = "CountyID";
lkuResidenceCounty.Properties.Columns[0].Visible = false;
lkuResidenceCounty.Properties.Columns[2].Visible = false;
lkuResidenceCounty.Properties.Columns[3].Visible = false;
This works just fine as the CountyName is displayed as expected.
However, When I try and load an existing member's value for this field using the below, which is part of a function that takes a row from the DataSet -->
lkuResidenceCounty.Properties.ValueMember = row["ResidencyCountyID"].ToString();
I get a blank box. I have stepped through the code and the correct ID is being returned for the member.
Unfortunately the stored procedure to fill the dropdown options pulls from a Maintenance Table with the columns "CountyName" & "CountyID". So that is correct. Unfortunately, the stored procedure to load a specific person's current county pulls from the Person Table where there is a column called "ResidencyCountyID". It is so named because there is also a "ResponsibilityCountyID" column.
I need a way for them both to coexist, any solutions?
Thanks!
DisplayMember and ValueMember are used to populate the control with the list of selectable values. To set the selected value of a populated LookUpEdit control, set its EditValue property:
lkuResidenceCounty.EditValue = row["ResidencyCountyID"].ToString();
In response to your edit: According to the documentation:
The currently selected row determines values for the editor's edit value and display text. The value for BaseEdit.EditValue is obtained from the RepositoryItemLookUpEditBase.ValueMember field, while the text to display in the edit box is obtained from the RepositoryItemLookUpEditBase.DisplayMember field of the selected row.
When you change BaseEdit.EditValue,
the editor locates and selects the row
whose
RepositoryItemLookUpEditBase.ValueMember
field contains the new value. The text
in the edit box is changed to reflect
the newly selected row.
I don't use these controls but it sounds to me that it shouldn't be working as you described. I think the ToString() is the problem because EditValue accepts an object so it's probably expecting an int for the value. Try:
lkuResidenceCounty.EditValue = (int)row["ResidencyCountyID"];
The ValueMember property tells the list what field to pull from when setting the Value property. Once you've set the ValueMember to "CountyID", then when the list is Databound, it will set all the list items' value properties to their respect objects' CountyID fields.
Hence, you should not do:
lkuResidenceCounty.Properties.ValueMember = row["ResidencyCountyID"].ToString();
but rather
lkuResidenceCounty.Properties.ValueMember = "CountyID";
was perfectly fine, as long as you've correctly identified the field you're trying to databind. Once the list get's databound you should see the results you're expecting.
However, after looking at your code, it seems that you're mismatching your field. In one place you're using ResidencyCountyID and in another you're using CountyID. That is most likely your source of confusion. Figure out what the actual field name is and make sure you set the ValueMember to that.
UPDATE
After reading your comment, what your looking for is the SelectedValue property. The SelectedValue property tells the list to force the selected value to whatever input you give it.
Essentially you have two things going on here. ValueMember tells the list what to use as the value from your data source, and SelectedValue which tells the list what the currently selected value should be.
Why is it that you need the same LookUpEdit to have two value members? Is it being used standalone or in a grid? If standalone, you could swap out the two repository editors depending on the current row. But, are there more than 2 possible values for the ValueMember? That would also complicate things.
UPDATE
Looking at your edit, I think I understand what's going on a little more. So, you don't wish to change your ValueMember (which refers to a data column), but rather to change the value of the editor? If so, then you should definitely use EditValue (not SelectedText, which I don't believe is meant to be set), and assign it to row["value_field"] like so:
lkuResidenceCounty.EditValue = row["ResidencyCountyID"];
What happens when you do that?