如何将 textblock.foreground 绑定到变量?(WPF C#) [英] How to bind textblock.foreground to a variable? (WPF C#)
问题描述
所以我希望改变我的程序，以便我可以运行一个函数来检查前景色是否应该是黑色或银色.我希望将不可访问"的字段灰显.
So I am hoping to alter my program such that I can run a function to check and see if the foreground color should be black or silver. I am hoping to gray out fields that are not "accessible".
我的表单目前看起来像:
My form currently looks like:
我希望将无需维护"字段变灰".但是我在尝试为数据模板中的字体前景定义绑定元素时遇到问题.
I was hoping to "gray out" the "No maintenance required" fields. But I am having problems with trying to define a binding element to the font foreground in my data template.
我已经尝试了从尝试在主窗口代码中定义 IValueConverter 类到定义窗口键资源的所有方法，但我似乎无法在文本块元素本身的数据模板中执行此操作?
I've tried everything from trying to define an IValueConverter class within the main window code behind, to defining a window key resource, but it doesn't appear that I can do that within a data template on the textblock element itself?
任何建议/帮助将不胜感激.谢谢！
Any suggestions/help would be appreciated. Thanks!
XAML:
<Grid Margin="0,0,2,0">
<ListBox x:Name="allSites_LB"
HorizontalAlignment="Left"
Height="400"
Margin="20,60,0,0"
VerticalAlignment="Top"
Width="945"
Loaded="allSites_LB_Loaded"
BorderThickness="1" SelectionChanged="allSites_LB_SelectionChanged"
ScrollViewer.HorizontalScrollBarVisibility="Disabled"
>
<ListBox.ItemTemplate >
<DataTemplate >
<Border BorderBrush="Black" BorderThickness="0,0,0,1" Margin="-20,1,0,1" Padding="0,5,0,5" >
<Grid Margin="75,3" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="400" />
<ColumnDefinition Width="345" />
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding SiteNo}" Grid.Column="0" FontSize="16" />
<TextBlock Text="{Binding Address}" Grid.Column="1" FontSize="16" Margin="50,1" />
<TextBlock Text="{Binding MaintStatus}" Grid.Column="2" FontSize="16" />
</Grid>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button x:Name="viewHistory_BTN"
Content="View History"
HorizontalAlignment="Left"
Height="52"
Margin="20,496,0,0"
VerticalAlignment="Top"
Width="172" FontSize="20"
/>
<Button x:Name="startMaintenance_BTN"
Content="Start Maintenance"
HorizontalAlignment="Left"
Height="52"
Margin="793,496,0,0"
VerticalAlignment="Top"
Width="172" FontSize="20"
/>
<TextBox x:Name="Site_Address"
HorizontalAlignment="Left"
Height="21"
Margin="51,39,0,0"
TextWrapping="Wrap"
Text="Site Number"
VerticalAlignment="Top"
Width="75"
BorderBrush="White"
IsReadOnly="True"
IsEnabled="False"
/>
<TextBox x:Name="Address_Title"
HorizontalAlignment="Left"
Height="21"
Margin="380,34,0,0"
TextWrapping="Wrap"
Text="Address"
VerticalAlignment="Top"
Width="75"
BorderBrush="White"
IsReadOnly="True"
IsEnabled="False"
/>
<TextBox x:Name="maint_Title"
HorizontalAlignment="Left"
Height="21"
Margin="699,34,0,0"
TextWrapping="Wrap"
Text="Maintenance Record"
VerticalAlignment="Top"
Width="117"
BorderBrush="White"
IsReadOnly="True"
IsEnabled="False"
/>
</Grid>
背后的C#代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data.SqlClient;
namespace SiteMaintenance
{
public partial class MainWindow : Window
{
/**
* CLASS VARIABLES
* */
private SqlConnection localdbConnection; // Connection to Site Maintenance DB (LOCAL)
private System.Data.DataSet allSitesResults;
// MAIN THREAD
public MainWindow()
{
InitializeComponent();
// try to open SQL Connection
try {
localdbConnection = new SqlConnection(Properties.Settings.Default.localdb);
localdbConnection.Open();
} catch(Exception ex) {
System.Windows.MessageBox.Show("local SQL connection unable to connect");
return;
}
viewHistory_BTN.IsEnabled = false;
startMaintenance_BTN.IsEnabled = false;
startMaintenance_BTN.IsDefault = true;
}
/**
* Load dataset into datagrid
* LAZY LOADING
* */
private void DataGrid_Loaded(object sender, RoutedEventArgs e)
{
// init command object
SqlCommand myCommand = new SqlCommand();
myCommand.CommandText = "dbo.usp_GetSites";
myCommand.CommandType = System.Data.CommandType.StoredProcedure;
myCommand.Connection = localdbConnection;
// init data adaptor
SqlDataAdapter sites = new SqlDataAdapter();
sites.SelectCommand = myCommand;
//init DataSet
allSitesResults = new System.Data.DataSet();
sites.Fill(allSitesResults, "tblSites");
int tableCount = allSitesResults.Tables.Count;
System.Data.DataTable test = allSitesResults.Tables[0];
int rowCount = test.Rows.Count;
}
private void sites_DG_CurrentCellChanged(object sender, EventArgs e)
{
String siteName = allSitesResults.Tables[0].Rows[0][1].ToString();
}
private void allSites_LB_Loaded(object sender, RoutedEventArgs e)
{
// init command object
SqlCommand myCommand = new SqlCommand();
myCommand.CommandText = "dbo.usp_GetSitesANDCompletedDate";
myCommand.CommandType = System.Data.CommandType.StoredProcedure;
myCommand.Connection = localdbConnection;
// init data adaptor
SqlDataAdapter sites = new SqlDataAdapter();
sites.SelectCommand = myCommand;
//init DataSet
allSitesResults = new System.Data.DataSet();
sites.Fill(allSitesResults, "tblSites");
allSites_LB.ItemsSource = allSitesResults.Tables["tblSites"].DefaultView;
}
// do not allow selection of maintenance records that do not exist
private void allSites_LB_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
// grab the index
int selectedIndex = allSites_LB.SelectedIndex;
if (selectedIndex == -1) return; //WITHOUT THIS CHECK, UN-SELECTION WILL CAUSE LOGIC FAILURE
System.Data.DataRowView tempData = (System.Data.DataRowView)allSites_LB.Items[allSites_LB.SelectedIndex];
// grab the completed date field
String completedDate = tempData["CompletedDate"].ToString();
String siteMaintID = tempData["SiteMaintID"].ToString();
// remove selected index if completed date and site Maint ID is null
if (siteMaintID != "" && completedDate == "")
{
startMaintenance_BTN.IsEnabled = true;
}
else
{
allSites_LB.SelectedIndex = -1;
startMaintenance_BTN.IsEnabled = false;
}
}
private String maintRequired(object sender, SelectionChangedEventArgs e)
{
int selectedIndex = allSites_LB.SelectedIndex;
if (selectedIndex < 0) return null;
System.Data.DataRowView tempData = (System.Data.DataRowView)allSites_LB.Items[allSites_LB.SelectedIndex];
// grab the completed date field
String completedDate = tempData["CompletedDate"].ToString();
String siteMaintID = tempData["SiteMaintID"].ToString();
if (siteMaintID != "" && completedDate == "")
{
return "Maintenance Required";
}
else
{
return "No Maintenance";
}
}
}
}
推荐答案
在将前景颜色绑定到一段数据时，通常有两种很好的方法供您选择.根据您询问的对象，不同的人会有不同的偏好.所以……两者都有！
There are generally two good approaches for you to choose from, when binding the Foreground color to a piece of data. Depending on who you ask, different people will have different preferences. So... here's both!
当满足一组特定条件时，此方法基本上可以识别特殊"行为.在这种情况下，我们将前景色更改为灰色，当状态 ==无需维护"
This method basically identifies 'special' behavior when a certain set of conditions are met. In this case, we're changing the foreground color to Gray, when the status == "No Maintenance Required"
<Style TargetType="TextBlock">
<Setter Property="Foreground" Value="Black" /> <!-- default value -->
<Style.Triggers>
<DataTrigger Binding="{Binding Text, RelativeSource={RelativeSource Self}" Value="No Maintenance Required">
<Setter Property="Foreground" Value="Gray" /> <!-- special behavior -->
</DataTrigger>
</Style.Triggers>
</Style>
在这种情况下，只需为您的 TextBlock 分配适当的 Style 属性.
In this case, just assign your TextBlock the appropriate Style property.
这种方法创建了一个自定义的IValueConverter 实现，它将您的文本值转换为颜色.从那里，我们直接绑定到我们的文本值，并确保转换器始终提供正确的颜色.
This approach creates a custom "IValueConverter implementation, which converts your Text value to a Color. From there, we bind directly to our text value, and ensure that the converter always provides the proper color.
public class MaintenaceColorConverter : IValueConverter
{
public Color NormalColor { get; set; }
public Color NoMaintenanceRequiredColor { get; set; }
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value.ToString() == "No Maintenance Required")
return NoMaintenanceRequiredColor;
return NormalColor;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
在您的 XAML 中:
In your XAML:
<Window.Resources>
<local:MaintenaceColorConverter x:Key="myColorConverter" NormalColor="Black" NoMaintenanceRequiredColor="Gray" />
</Window.Resources>
在您的文本块中:
<TextBlock Text="{Binding MaintStatus}" Foreground="{Binding MaintStatus, Converter={StaticResource myColorConverter}}" />
改进
使用这些方法中的任何一种，最好有一个 MaintenanceStatus 布尔值或枚举值，并将您的样式条件绑定到该值.使用字符串比较是一个坏主意.那只是自找麻烦.这些示例使用了字符串比较，因为……好吧……这就是您提供的示例代码中的全部内容.
Improvements
With either of these approaches, it would be better to have a MaintenanceStatus boolean or enum value, and bind your styling conditions to that. It's a bad idea to use string-comparisons. That's just begging for trouble. These examples used string comparison because... well... that's all that was available from your provided example code.
这篇关于如何将 textblock.foreground 绑定到变量?(WPF C#)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
