探测器设置界面增加图像灰度直方图，用于显示实时采集图像的灰度信息，优化图像灰度直方图的显示方式（无图像提示）和优化资源释放。

XP.Common/Controls/ImageHistogram/ImageHistogramControl.xaml

@@ -2,12 +2,18 @@
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
+             xmlns:loc="clr-namespace:XP.Common.Localization.Extensions"
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="d"
              d:DesignHeight="200" d:DesignWidth="400">
     <Grid>
+        <!-- 图表控件 | Chart control -->
         <telerik:RadCartesianChart x:Name="HistogramChart">
+            <!-- 禁用 Telerik 自带的无数据提示 | Disable Telerik built-in empty content -->
+            <telerik:RadCartesianChart.EmptyContent>
+                <TextBlock/>
+            </telerik:RadCartesianChart.EmptyContent>
             <!-- X 轴：灰度级别 | X Axis: Gray Level -->
             <telerik:RadCartesianChart.HorizontalAxis>
                 <telerik:LinearAxis x:Name="XAxis"
@@ -32,5 +38,14 @@
                                    ShowLabels="False"/>
             </telerik:RadCartesianChart.Series>
         </telerik:RadCartesianChart>
+
+        <!-- 无数据提示文本（叠加在图表上方）| No data placeholder text (overlaid on chart) -->
+        <TextBlock x:Name="NoDataPlaceholder"
+                   Text="{loc:Localization Histogram_NoData}"
+                   HorizontalAlignment="Center"
+                   VerticalAlignment="Center"
+                   FontSize="14"
+                   Foreground="#9E9E9E"
+                   Visibility="Visible"/>
     </Grid>
 </UserControl>