I have a DataGrid which has plenty rows and columns,
I want to get the cell ready for editing when the user focus the mouse on it (IsMouseOver).
So far, all I found is this
<Window.Resources>
<Style TargetType="{x:Type DataGridCell}">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="green"></Setter>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
I am able to set a property for the cell when the mouse is over it.
But how to launch an event when the mouse is over?
I would add an EventSetter in a Style like this :
<DataGrid.Resources>
<Style TargetType="{x:Type DataGridCell}">
<EventSetter Event="MouseEnter" Handler="EventSetter_OnHandler"/>
</Style>
</DataGrid.Resources>
Here is the handler:
private void EventSetter_OnHandler(object sender, MouseEventArgs e)
{
DataGridCell dgc = sender as DataGridCell;
TextBox tb = Utils.GetChildOfType<TextBox>(dgc);
tb.Focus();
}
In fact you said you want to edit something. In my case, there is a TextBox and i reach it with this helper:
public static T GetChildOfType<T>(DependencyObject depObj) where T : DependencyObject
{
if (depObj == null) return null;
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
var child = VisualTreeHelper.GetChild(depObj, i);
var result = (child as T) ?? GetChildOfType<T>(child);
if (result != null) return result;
}
return null;
}
After reaching it, a simple Focus() will do the final job.
You can launch a mouseover Event in Xaml Like this From where you have your DataGridCell
<DataGridCell MouseEnter="DataGridCell_MouseEnter"/>
Related
I have this code in my xaml which says to color my button when I hover my mouse and click my mouse over the button.
<Border x:Class="DatasetGrid.RowHeaderButton"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300" MinWidth="30" Width="Auto">
<Border.Resources>
<SolidColorBrush x:Key="ButtOverBrush" Color="#53C3D5" Opacity="0.2"></SolidColorBrush>
<SolidColorBrush x:Key="ButtPressedBrush" Color="#53C3D5" Opacity="0.5"></SolidColorBrush>
</Border.Resources>
<Border.Style>
<Style TargetType="Border">
<Setter Property="Background" Value="Transparent"></Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="{StaticResource ButtOverBrush}"></Setter>
</Trigger>
<DataTrigger Binding="{Binding IsMouseDown, RelativeSource={RelativeSource Self}}" Value="True">
<Setter Property="Background" Value="{StaticResource ButtPressedBrush}"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
</Border>
This works all well and good, but I find that as soon as I change the Background color in code behind, the above MouseOver and MouseDown triggers don't fire anymore.
RowHeaderButton rhb = RowHeadersColumn.VisibleRowHeaders[cell.CellInfo.RowIndex];
rhb.Background = new SolidColorBrush(Color.FromArgb(100, 83, 195, 213));
I'm quite new to WPF so I'm not sure what's going wrong.
Edit:
So to give some more information, my control above is a RowHeaderButton, i.e the row header to a grid. Each row in the grid has it's own row header button. So when the user hovers over or clicks it, it should change from white to the specified SolidColorBrush above.
In the code behind of another control, DataGrid.xaml.cs, I have the below code (simplified) which will change the color of the row header when when a cell in the same row of the grid is selected or not.
void UpdateSelectedCells() {
foreach (Cell cell in VisibleColumns.SelectMany(c => c.VisibleCells))
{
int cellRowIndex = cell.CellInfo.RowIndex;
cell.IsSelected = SelectedCells.Contains(cell.CellInfo);
foreach (RowHeaderButton rhb in RowHeadersColumn.VisibleRowHeaders)
{
int rowHeaderIndex = Convert.ToInt16(rhb._default.Text) - 1;
if (cellRowIndex == rowHeaderIndex)
{
if (cell.IsSelected)
{
rhb.Background = new SolidColorBrush(Color.FromArgb(100, 83, 195, 213));
}
else
{
bool rowselected = false;
//need to check if any other cell in the row is selected, if not then color row header white
foreach (CellInfo celll in SelectedCells)
{
if (celll.RowIndex == cellRowIndex)
{
rowselected = true;
break;
}
}
if (rowselected == false)
rhb.Background = Brushes.White;
}
}
}
}
}
I don't have a ViewModel for this.
The triggers are firing, but their setters are being overridden.
This is due to Dependency Property Value Precendence. If the Background property is set programmatically or as an attribute in the XAML, that value will override anything value any style setter gives it. In general, this is desirable behavior: You want to be able to override what the style does on an individual control.
The solution to this is to do all of your background brush changes in style triggers. Your code behind must have some reason for setting the background brush when it does. Whatever that is, find a way to do it with a trigger. Set a property on the viewmodel and write a trigger on that property.
If you need help translating that high level abstraction into your own code, please share enough code for me to understand why and where the codebehind is setting the Background, and what (if anything) you have for a viewmodel.
I solved the issue by creating a new Dependancy Property and binding it to a data trigger.
public bool IsCellSelected
{
get { return (bool)GetValue(IsCellSelectedProperty); }
set { SetValue(IsCellSelectedProperty, value); }
}
public static readonly DependencyProperty IsCellSelectedProperty =
DependencyProperty.Register("IsCellSelected", typeof(bool), typeof(RowHeaderButton), new PropertyMetadata(null));
In my xaml I have:
<DataTrigger Binding="{Binding IsCellSelected, RelativeSource={RelativeSource Self}}" Value="True">
<Setter Property="Background" Value="{StaticResource ButtPressedBrush}"></Setter>
</DataTrigger>
And in my code behind I set the value using:
RowHeaderButton rhb = RowHeadersColumn.VisibleRowHeaders[cell.CellInfo.RowIndex];
rhb.IsCellSelected = true; //or false
Now my button hover and button click events are not overridden.
Pre-Warning sorry WPF new guy here:
I have a DataGrid bound to a DataTable's DefaultView
ResultDataGrid.ItemsSource = resultTable.DefaultView;
I know the column names, and I need to change a column's foreground if another column is 1 (always 0 or 1)
Currently what I have:
private void ResultDataGrid_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
if (e.Column.Header.ToString() == "columnName")
{
e.Column.CellStyle = FindResource("columnStyle") as Style;
}
}
and in XAML:
<Window.Resources>
<Style TargetType="DataGridCell" x:Key="columnStyle">
<Setter Property="Foreground" Value="Black"/>
<Style.Triggers>
<DataTrigger Binding="{Binding resultTable, Path={StaticResource otherColumnName}}" Value="1">
<Setter Property="Foreground" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
Where otherColumnName is set in the constructor
public ResultsCustom(DataTable resultclass, CustomQuery query)
{
// Some other stuff
this.Resources.Add("otherColumnName", COLUMN_NAME);
}
The XAML Style seems to not have the correct path, any help would be appreciated!
I'm not sure about this line of code:
Path={StaticResource otherColumnName}
Are you attempting to compare the property "otherColumnName" of the resultTable to see if this is 1? This wouldn't be a static resource, and you could change your binding to:
Path=otherColumnName
I have a DataGrid with several columns in my application.. I need to use different row foreground colour in case of some certain field content. I use following callback on LoadingRowevent:
void userGrid_LoadingRow(object sender, DataGridRowEventArgs e){
if (e.Row.Item != null){
// check some row's field value
...
// modify row forecolor
e.Row.Foreground = new SolidColorBrush(Colors.Red);
...
}
}
But how to get value of some certain row's field by it's name or index?
void userGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
var dataGrid = (DataGrid)sender;
IEnumrable<DataGridRow> rows = dataGrid.Items.Where(r => (r.DataContext as YourItemsSourceEntity).SomeProperty == yourCondition)
}
Alternatively i would add a condition to your ItemsSource .
public class YourItemsSourceEntity
{
public bool IsSomething { get; }
}
xaml :
<DataGrid ItemsSource="{Binding Items}">
<DataGrid.ItemContainerStyle>
<Style TargetType="DataGridRow">
<Style.Triggers>
<DataTrigger Binding="{Binding IsSomething}" Value="True">
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</DataGrid.ItemContainerStyle>
</DataGrid>
as to the comment below : Is this what you ment ?
void userGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
var item = e.Row.DataContext as (YourItemsSourceEntity);
var id = item.ID ;
}
Is there any way to achieve something like office undo drop down (image bellow) ?
I mean, i want to highlight previous item when user mouse over item other than first ?
I tried some control from FluentRibbon but so far without luck..
In most cases designing a control like this is done in Blend. However, if you don't know how to use Blend, you can still achieve the similar results with just XAML and the code-behind, but you have to do more work.
We start by creating a class called CustomListBoxItem which inherits from ListBoxItem. Then, we define a dependency property, which is used for highlighting items in the listbox:
public class CustomListBoxItem : ListBoxItem
{
public static readonly DependencyProperty IsVirtuallySelectedProperty =
DependencyProperty.Register("IsVirtuallySelected", typeof(bool),
typeof(CustomListBoxItem),
new PropertyMetadata(false));
public CustomListBoxItem() : base()
{ }
public bool IsVirtuallySelected
{
get { return (bool)GetValue(IsVirtuallySelectedProperty); }
set { SetValue(IsVirtuallySelectedProperty, value); }
}
}
Then we add a listbox and define a style for it in XAML:
<ListBox Name="listBox" MouseMove="listBox_MouseMove" SelectionChanged="listBox_SelectionChanged">
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type local:CustomListBoxItem}">
<Style.Triggers>
<Trigger Property="IsVirtuallySelected" Value="true">
<Setter Property="Background" Value="SkyBlue"/>
</Trigger>
<Trigger Property="IsVirtuallySelected" Value="false">
<Setter Property="Background" Value="White"/>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
where local is the namespace in which CustomListBoxItem is defined. This is all we need for the XAML part, the real magic happens in the code behind.
The listBox_MouseMove event handler looks like this:
private void listBox_MouseMove(object sender, MouseEventArgs e)
{
bool itemFound = false;
for (int i = 0; i < listBox.Items.Count; i++)
{
var currentItem = listBox.ItemContainerGenerator.ContainerFromIndex(i) as CustomListBoxItem;
if (currentItem == null)
continue;
// Check whether the cursor is on an item or not.
if (IsMouseOverItem(currentItem, e.GetPosition((IInputElement)currentItem)))
{
// Unselect all items before selecting the new group
listBox.Items.Cast<CustomListBoxItem>().ToList().ForEach(x => x.IsVirtuallySelected = false);
// Select the current item and the ones above it
for (int j = 0; j <= listBox.Items.IndexOf(currentItem); j++)
{
((CustomListBoxItem)listBox.Items[j]).IsVirtuallySelected = true;
}
itemFound = true;
break;
}
}
// If the item wasn't found for the mouse point, it means the pointer is not over any item, so unselect all.
if (!itemFound)
{
listBox.Items.Cast<CustomListBoxItem>().ToList().ForEach(x => x.IsVirtuallySelected = false);
}
}
And the IsMouseOverItem helper method, which is used to determine if the cursor is on an item, is defined like this:
private bool IsMouseOverItem(Visual item, Point mouseOverPoint)
{
Rect currentDescendantBounds = VisualTreeHelper.GetDescendantBounds(item);
return currentDescendantBounds.Contains(mouseOverPoint);
}
And finally the listBox_SelectedChanged event handler which acts as the click handler for the ListBox:
private void listBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
// Get all the virtually selected items
List<CustomListBoxItem> selectedItems =
listBox.Items.Cast<CustomListBoxItem>().Where(x => x.IsVirtuallySelected).ToList();
if (selectedItems == null || !selectedItems.Any())
return;
// Do something with the selected items
DoCoolStuffWithSelectedItems();
// Unselsect all.
listBox.Items.Cast<CustomListBoxItem>().ToList().ForEach(x => x.IsVirtuallySelected = false);
listBox.UnselectAll();
}
And boom, we're done. We can now add some items to the ListBox in the class constructor:
public MainWindow()
{
InitializeComponent();
listBox.Items.Add(new CustomListBoxItem { Content = "hello world!" });
listBox.Items.Add(new CustomListBoxItem { Content = "wpf is cool" });
listBox.Items.Add(new CustomListBoxItem { Content = "today is tuesday..." });
listBox.Items.Add(new CustomListBoxItem { Content = "I like coffee" });
}
Note that I used a random color as the highlight color in XAML. Feel free to change it and give it a try.
Guess you need something like this:
<ControlTemplate TargetType="ListBoxItem">
<TextBlock Text="{Binding LastOperation}">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger>
<DataTrigger.Binding>
<MultiBinding>
<Binding Path="MouseOverIndex"/>
<Binding Path="CurrentIndex"/>
</MultiBinding>
</DataTrigger.Binding>
<Setter Property="Foreground" Value="Gold"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</ControlTemplate>
I'm still fighting with manipulation of cell backgrounds so I'm asking a new question.
A user "H.B." wrote that I can actually set the cell style during the AutoGeneratingColumn event - Change DataGrid cell colour based on values. The problem is that I'm not sure how to do it.
What I want:
Set different background colours for each cell depending on its value. If the value is null I also want it not to be clickable (focusable I guess).
What I have / I'm trying to do:
private void mydatagrid_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
foreach (Cell cell in e.Column)
{
if (cell.Value < 1)
{
cell.Background = Color.Black;
cell.isFocusable = false;
}
else
{
cell.Background = Color.Pink;
}
}
}
This is just the pseudocode. Is something like this is possible during column auto-generation and if so, how can I edit my code so it will be valid?
I read about value convertors but I want to know if it's somehow possible programmatically, without writing XAML.
Please understand that I'm still a beginner to C#/WPF/DataGrid.
Solution part1:
I used the answer I accepted. Just put it into
<Window.Resources>
<local:ValueColorConverter x:Key="colorConverter"/>
<Style x:Key="DataGridCellStyle1" TargetType="{x:Type DataGridCell}">
<Setter Property="Padding" Value="5"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridCell}">
<Border Padding="{TemplateBinding Padding}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="True">
<Border.Background>
<MultiBinding Converter="{StaticResource colorConverter}">
<Binding RelativeSource="{RelativeSource AncestorType=DataGridCell}" Path="Content.Text"/>
<Binding RelativeSource="{RelativeSource AncestorType=DataGridCell}" Path="IsSelected"/>
</MultiBinding>
</Border.Background>
<ContentPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
And made for it a MultiBinding convertor so I can also set the background color for selected cells.
Problem:
Now I only have to solve the problem of setting focus of empty cells. Any hints?
<Style.Triggers>
<Trigger Property="HasContent" Value="False">
<Setter Property="Focusable" Value="False"/>
</Trigger>
</Style.Triggers>
This doesn't work. I had empty strings in the empty cells, but they are filled with ´null´s so it should work, right? Or what am I doing wrong :| ?
Solution part 2:
So the code above won't work as long as the cell value is a ´TextBox´ so I decided to find another way to deal with it which can be found in my answer here: https://stackoverflow.com/a/16673602/2296407
Thanks for trying to help me :)
I can propose two different solutions for your question: the first is "code-behind-style" (which you are asking for but personally I think it is not right approach in WPF) and more WPF-style (which more tricky but keeps code-behind clean and utilizes styles, triggers and converters)
Solution 1. Event handling and code-behind logic for coloring
First of all, the approach you've chosen will not work directly - the AutoGeneratingColumn event is meant to be used for altering the entire column appearance, not on the cell-by-cell basis. So it can be used for, say, attaching the correct style to entire column basing on it's display index or bound property.
Generally speaking, for the first time the event is raised your datagrid will not have any rows (and consequently - cells) at all. If you really need to catch the event - consider your DataGrid.LoadingRow event instead. And you will not be able to get the cells that easy :)
So, what you do: handle the LoadingRow event, get the row (it has the Item property which holds (surprisingly :)) your bound item), get the bound item, make all needed calculations, get the cell you need to alter and finally alter the style of the target cell.
Here is the code (as item I use a sample object with the int "Value" property that I use for coloring).
XAML
<DataGrid Name="mygrid" ItemsSource="{Binding Items}" AutoGenerateColumns="True" LoadingRow="DataGrid_OnLoadingRow"/>
.CS
private void DataGrid_OnLoadingRow(object sender, DataGridRowEventArgs e)
{
Dispatcher.BeginInvoke(DispatcherPriority.Render, new Action(() => AlterRow(e)));
}
private void AlterRow(DataGridRowEventArgs e)
{
var cell = GetCell(mygrid, e.Row, 1);
if (cell == null) return;
var item = e.Row.Item as SampleObject;
if (item == null) return;
var value = item.Value;
if (value <= 1) cell.Background = Brushes.Red;
else if (value <= 2) cell.Background = Brushes.Yellow;
else cell.Background = Brushes.Green;
}
public static DataGridRow GetRow(DataGrid grid, int index)
{
var row = grid.ItemContainerGenerator.ContainerFromIndex(index) as DataGridRow;
if (row == null)
{
// may be virtualized, bring into view and try again
grid.ScrollIntoView(grid.Items[index]);
row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromIndex(index);
}
return row;
}
public static T GetVisualChild<T>(Visual parent) where T : Visual
{
T child = default(T);
int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < numVisuals; i++)
{
var v = (Visual)VisualTreeHelper.GetChild(parent, i);
child = v as T ?? GetVisualChild<T>(v);
if (child != null)
{
break;
}
}
return child;
}
public static DataGridCell GetCell(DataGrid host, DataGridRow row, int columnIndex)
{
if (row == null) return null;
var presenter = GetVisualChild<DataGridCellsPresenter>(row);
if (presenter == null) return null;
// try to get the cell but it may possibly be virtualized
var cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);
if (cell == null)
{
// now try to bring into view and retreive the cell
host.ScrollIntoView(row, host.Columns[columnIndex]);
cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);
}
return cell;
}
Solution 2. WPF-style
This solution uses code-behind only for value-to-color convertions (assuming that that logic of coloring is more complex than equality comparison - in that case you can use triggers and do not mess with converters).
What you do: set DataGrid.CellStyle property with style that contains a data trigger, which checks if the cell is within a desired column (basing on it's DisplayIndex) and if it is - applies background through a converter.
XAML
<DataGrid Name="mygrid" ItemsSource="{Binding Items}" AutoGenerateColumns="True">
<DataGrid.Resources>
<local:ValueColorConverter x:Key="colorconverter"/>
</DataGrid.Resources>
<DataGrid.CellStyle>
<Style TargetType="DataGridCell">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Column.DisplayIndex}" Value="1">
<Setter Property="Background" Value="{Binding RelativeSource={RelativeSource Self}, Path=Content.Text, Converter={StaticResource colorconverter}}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</DataGrid.CellStyle>
</DataGrid>
.CS
public class ValueColorConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var str = value as string;
if (str == null) return null;
int intValue;
if (!int.TryParse(str, out intValue)) return null;
if (intValue <= 1) return Brushes.Red;
else if (intValue <= 2) return Brushes.Yellow;
else return Brushes.Green;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
UPD: If you need to color entire datagrid, XAML is much easier (no need to use triggers). Use the following CellStyle:
<DataGrid.CellStyle>
<Style TargetType="DataGridCell">
<Setter Property="Background" Value="{Binding RelativeSource={RelativeSource Self}, Path=Content.Text, Converter={StaticResource colorconverter}}"/>
</Style>
</DataGrid.CellStyle>
What i meant is that you can set the CellStyle property of the column, you can not manipulate cells directly as they are not available in this event. The style can contain your conditional logic in the form of DataTriggers (will need a converter as you have "less-than" and not equals) and Setters.
Also if the logic is not specific to the columns you can set the style globally on the grid itself. The point of using the event would be to manipulate the column properties which you can not access otherwise.
I am not sure whether this property (Cell.Style) is available in your WPF Datagrid. Probably some alternative exists in your case. It has worked for WinForms datagrid.
cell.Style.BackColor = System.Drawing.Color.Black;