I am binding the Grid with a business object which contains a field Country (which is another business object containing ID and Name). I want to display the country name set to the "Country" in the business object for each row. However if the user wishes to change the country then I want to show the user a drop down list with all the countries available.
I'm stuck with getting the SlectedValue from the repositoryItemLookUpEdit and setting the Selected value
All you should have to do is assign a RepositoryItemLookupEdit to the Column.Edit property.
Then in your RepositoryItemLookupEdit set the Datasource to a IList of all your Country objects.
Set the RepositoryItemLookupEdit.DisplayMember to "Name" and leave ValueMember as blank (this will make the object itself the value)
Then your grid should handle everything for you, as if you click on the dropdown and select a new country the selected Country object will be assigned to that cell's value.
Keep in mind however that the Objects much be the same Reference match... ie. If your Business Objects Country object isn't apart of the IList of Countries then it won't display a value.
Are you using XPO at all?
I Solved this using a ComboBox instead of a LookupEdit and it worked without problem.
Related
What is the difference betweeen the following:
SelectedItem
SelectedValue
SelectedValuePath
All these dependency properties are defined in Selector class. I often confuse SelectedItem with SelectedValue , and SelectedValue with SelectedValuePath.
I would like to know the difference between them, and also when do we use them, especially SelectedValue and SelectedValuePath. Please explain their use with some simple examples.
Their names can be a bit confusing :). Here's a summary:
The SelectedItem property returns the entire object that your list is bound to. So say you've bound a list to a collection of Category objects (with each Category object having Name and ID properties). eg. ObservableCollection<Category>. The SelectedItem property will return you the currently selected Category object. For binding purposes however, this is not always what you want, as this only enables you to bind an entire Category object to the property that the list is bound to, not the value of a single property on that Category object (such as its ID property).
Therefore we have the SelectedValuePath property and the SelectedValue property as an alternative means of binding (you use them in conjunction with one another). Let's say you have a Product object, that your view is bound to (with properties for things like ProductName, Weight, etc). Let's also say you have a CategoryID property on that Product object, and you want the user to be able to select a category for the product from a list of categories. You need the ID property of the Category object to be assigned to the CategoryID property on the Product object. This is where the SelectedValuePath and the SelectedValue properties come in. You specify that the ID property on the Category object should be assigned to the property on the Product object that the list is bound to using SelectedValuePath='ID', and then bind the SelectedValue property to the property on the DataContext (ie. the Product).
The example below demonstrates this. We have a ComboBox bound to a list of Categories (via ItemsSource). We're binding the CategoryID property on the Product as the selected value (using the SelectedValue property). We're relating this to the Category's ID property via the SelectedValuePath property. And we're saying only display the Name property in the ComboBox, with the DisplayMemberPath property).
<ComboBox ItemsSource="{Binding Categories}"
SelectedValue="{Binding CategoryID, Mode=TwoWay}"
SelectedValuePath="ID"
DisplayMemberPath="Name" />
public class Category
{
public int ID { get; set; }
public string Name { get; set; }
}
public class Product
{
public int CategoryID { get; set; }
}
It's a little confusing initially, but hopefully this makes it a bit clearer... :)
Chris
To answer a little more conceptually:
SelectedValuePath defines which property (by its name) of the objects bound to the ListBox's ItemsSource will be used as the item's SelectedValue.
For example, if your ListBox is bound to a collection of Person objects, each of which has Name, Age, and Gender properties, SelectedValuePath=Name will cause the value of the selected Person's Name property to be returned in SelectedValue.
Note that if you override the ListBox's ControlTemplate (or apply a Style) that specifies what property should display, SelectedValuePath cannot be used.
SelectedItem, meanwhile, returns the entire Person object currently selected.
(Here's a further example from MSDN, using TreeView)
Update: As #Joe pointed out, the DisplayMemberPath property is unrelated to the Selected* properties. Its proper description follows:
Note that these values are distinct from DisplayMemberPath (which is defined on ItemsControl, not Selector), but that property has similar behavior to SelectedValuePath: in the absence of a style/template, it identifies which property of the object bound to item should be used as its string representation.
SelectedItem and SelectedValue are an object.
and SelectedValuePath is a string.
for example using the ListBox:
Below listbox1.SelectedValue becomes a string value.
string value = listbox1.SelectedValue;
if you say give me listbox1.SelectedItem it will give you the entire object.
ListItem item = listbox1.SelectedItem;
string value = item.value;
inspired by this question I have written a blog along with the code snippet here. Below are some of the excerpts from the blog
SelectedItem – Selected Item helps to bind the actual value from the DataSource which will be displayed. This is of type object and we can bind any type derived from object type with this property. Since we will be using the MVVM binding for our combo boxes in that case this is the property which we can use to notify VM that item has been selected.
SelectedValue and SelectedValuePath – These are the two most confusing and misinterpreted properties for combobox. But these properties come to rescue when we want to bind our combobox with the value from already created object. Please check my last scenario in the following list to get a brief idea about the properties.
Every control that uses Collections to store data have SelectedValue, SelectedItem property. Examples of these controls are ListBox, Dropdown, RadioButtonList, CheckBoxList.
To be more specific if you literally want to retrieve Text of Selected Item then you can write:
ListBox1.SelectedItem.Text;
Your ListBox1 can also return Text using SelectedValue property if value has set to that before. But above is more effective way to get text.
Now, the value is something that is not visible to user but it is used mostly to store in database. We don't insert Text of ListBox1, however we can insert it also, but we used to insert value of selected item. To get value we can use
ListBox1.SelectedValue
Source
I have used two entity classes for binding values into DataGridView. One is Estimates and Companies.
Estimates has columns such as "Id, Estimate Number, Estimate Amount, CompanyId".
Companies has columns such as "Id, Company Name, Address"
I have created two BindingSource such as EstimateBindingSource and CompanyBindingSource.
CompanyBindingSource has DataSource as EstimateBindingSource and DataMember as Estimates
EstimateBindingSource has DataSource as Estimates entity Class and no DataMember defined.
I have bound the EstimateBindingSource into the DataGridView using grid DataSource.
Here, I need to show Estimate number, Estimate Amount and Company Name in DataGridView.. I have't able to achieve this.
Note: I do not do any code behind logic to do this.. Need to achieve this only using design.
Options to show Second Level Properties in DataGridView
To show a sub property of your navigation property you can use either of these options:
Use a DataGridViewComboBox column and bind it to CompanyId and set it's DataSource to list of companies, and DisplayMember property to Name property of company and ValueMember to Id property of company.
Override ToString() method of Company class and return Name of company. Then show Company navigation property in grid.
Create a CompanyName property for your Estimate which returns its Company.Name value and show CompanyName in grid.
Using CellFormatting event of DataGridView and set e.Value to desired value (company name) you want to display in cell.
Shape your Estimates list using a Linq query or use a ViewModel and pass the result to data grid view.
Create a TypeDescriptor for your Estimate type to resolve second level properties.
.
To show a property of company instead of company id, you can use a DataGridViewComboBoxColumn.
Using ComboBox Column
Since you requested for a mechanism which uses designer without writing code I describe this option more. Here is settings you should perform:
EstimatesBindingSource should bind to a list of Estimates
The DataGridView should bind to EstimatesBindingSource
CompanyBindingSource is only used as data source of the combo box column and should be filled using a list of Companies
To show CompanyName in Estimates list, it's enough to use a DataGridViewComboBoxColumn and set it's DataSource to list of companies and set the DisplayMember to CompanyName and it's value member to Id. And bind it to CompanyId field of Estimate.
Also if your requirement is to don't show it as ComboBox, simply set DisplayStyle property of DataGridViewComboBoxColumn to Nothing. It removes dropdown style.
You also may find this post helpful:
Show Properties of a Navigation Property in DataGridView (Second Level Properties)
C# project with WinForm with Custom Classes, List<>, enums and Datagridview.
I have a class called CStaff, with enums with race, gender, role, wagetype etc.
Userinput
Then store all the different staff objects in a List<>.
List<> gets Saved/Loaded - Not relevant here.
Then I bind the List<> to the datagridview with the DataSource property.
datagrid.datasource = somelist;
This works fine, as it creates columns for all the normal properties for the CStaff object.
But it does not create columns for the enum properties.
Is there a way to force it to create them as well? Or a better way? Also, I would appreciate any links on how to control which properties should be used. At the moment it uses all of them (except the enums).
Any help greatly appreciated!
If you know which properties you want to show and the number of columns of your grid are fixed , you can set AutoGenerateColumns to false.
And manually map the column to the properties of your collection.
You can then use the DataGridViewComboBoxColumn to display the enum values as a combo-box.
In my Windows Mobile .NET application I have a simple array of object with the data I want to display in my DataGrid. To do this, I simply call:
myDataGrid.DataSource = myArray;
This works, but I have a problem with it: it uses all properties as columns and uses the names of the properties as the column headers. I can't figure out how to customize two things:
Select which subset of properties should be displayed as columns (say I have an ID, Name and Value property, I'd only want to show Name and Value);
Rename the column headers to make more sense (for example if the property is called ID display a column header saying "Number").
Is this possible at all?
As mentioned this is in a Windows Mobile .NET (version 2) application.
You need to set the Datagrid.TableStyles property to customize the layout.
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagrid.tablestyles.aspx
More details on binding to an array of objects here:
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridtablestyle.mappingname(VS.71).aspx
To bind the
System.Windows.Forms.DataGrid to a
strongly typed array of objects, the
object must contain public properties.
To create a DataGridTableStyle that
displays such an array, set the
MappingName property to classname[]
where classname is replaced by the
class name. Also note that the
MappingName property is
case-sensitive.
I don't know if you know the name of the columns in advance? But if it's the case, you can go in the "Edit Columns" of your DataGridView and just create your columns there. In the "Data" Category, change the "DataPropertyName" from "(none)" to the name of the class property. From there you can customize the name, if it's visible, the size, etc. The DataGrid will bind it to your DataSource.
Also, there is a property "DataGridView.AutoGenerateColumns" that you can set to false so you don't have to bind all the properties of your object. I tought that migh help as well.
In this code _im is an object of table and I bind this object with DataGridView dgvItem after binding I change header text of dgvItem as required.
dgvItem.Rows.Clear();
dgvItem.DataSource = _im ;
dgvItem.Columns[2].HeaderText = "Mobile Code";
dgvItem.Columns[3].HeaderText = "Mobile Name";
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?