Question

我必须在WPF应用程序中动态更新字体大小。在性能方面，哪种方法更好？以下两种方法的优缺点是什么？

合并字典[请参阅API OnFontSizeChanged_MergeDictionary]
更新资源密钥[请参阅API OnFontSizeChanged_UpdateResourceKey]

我已经在GenericResourceDictionary.xaml中定义了所有使用的FontSizes：

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:System="clr-namespace:System;assembly=mscorlib">

    <System:Double x:Key="FontSize_Small">12</System:Double>
    <System:Double x:Key="FontSize_Default">14</System:Double>
    <System:Double x:Key="FontSize_DefaultPlus">16</System:Double>
    <System:Double x:Key="FontSize_HeaderNormal">18</System:Double>
    <System:Double x:Key="FontSize_HeaderLarge">20</System:Double>
    <System:Double x:Key="FontSize_MenuItem">26</System:Double>

</ResourceDictionary>

用户启动的ViewModel中的运行时FonstSize更改：

方法＃1：创建一个新的ResourceDictionary并将其合并。删除旧的字体大小字典（我不删除GenericResourceDictionary.xmal，因为它的样式比字体更多）

    private void OnFontSizeChanged_MergeDictionary(string fontSize)
            {

                string currentDefaultFontSize = Application.Current.Resources["FontSize_Default"]!=null ? Application.Current.Resources["FontSize_Default"].ToString() : null;

                //If Current default fontsize is equal to what user is trying to set, then do nothing
                if ((currentDefaultFontSize == fontSize) || fontSize.IsNullOrEmpty())
                    return;

                double newDefaultFontSize = Convert.ToDouble(fontSize);

                ResourceDictionary rd = new ResourceDictionary();
                rd.Add("FontSize_Small", newDefaultFontSize - 2);
                rd.Add("FontSize_Default", newDefaultFontSize);
                rd.Add("FontSize_DefaultPlus", newDefaultFontSize + 2);
                rd.Add("FontSize_HeaderNormal", newDefaultFontSize + 4);
                rd.Add("FontSize_HeaderLarge", newDefaultFontSize + 6);
                rd.Add("FontSize_MenuItem", newDefaultFontSize + 12);

               //Unload old fontSizeResource
Application.Current.Resources.MergedDictionaries.Remove(_fontSizeRD);

              //Load new fontSizeResource
Application.Current.Resources.MergedDictionaries.Add(resource);

             //assign the new resource to class variable
_fontSizeRD=resource;
            }

方法2：GenericResourceDictionary.xaml中的资源密钥已更新

private void OnFontSizeChanged_UpdateResourceKey(string fontSize)
            {

                string currentDefaultFontSize = Application.Current.Resources["FontSize_Default"]!=null ? Application.Current.Resources["FontSize_Default"].ToString() : null;

                //If Current default fontsize is equal to what user is trying to set, then do nothing
                if ((currentDefaultFontSize == fontSize) || fontSize.IsNullOrEmpty())
                    return;

                double newDefaultFontSize = Convert.ToDouble(fontSize);

                Application.Current.Resources["FontSize_Small"] = newDefaultFontSize - 2;
                Application.Current.Resources["FontSize_Default"] = newDefaultFontSize;
                Application.Current.Resources["FontSize_DefaultPlus"] = newDefaultFontSize + 2;
                Application.Current.Resources["FontSize_HeaderNormal"] = newDefaultFontSize + 4;
                Application.Current.Resources["FontSize_HeaderLarge"] = newDefaultFontSize + 6;
                Application.Current.Resources["FontSize_MenuItem"] = newDefaultFontSize + 12;
            }

谢谢

RDV

WPF性能影响ResourceDictionary合并与更新

0 个答案: