wpf fire绑定源中的PropertyChanged事件,绑定得到更新

时间:2015-03-19 15:03:51

标签: c# .net wpf xaml custom-controls

我正在尝试使用验证功能制作一些CustomControl文本框。 (例如,仅限数字的文本框或邮政编码文本框等) 它应该在.dll库文件中实现。

我的项目包含文本框的CustomControl,一个处理验证的类, 和一个应该在TextBlock中显示错误消息的ErrMsgGui CustomControl (例外:只允许数字......)

我的问题是,当调用验证类中的方法时,我没有更新TextBlock Text

有没有办法触发PropertyChangeEvent来更新validaiton类中的Textblock文本?

(我对wpf很新)

Generic.xaml:

<Style TargetType="{x:Type local:NumTb}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:NumTb}">
                    <TextBox Background="{TemplateBinding Background}" Text="{Binding Source={StaticResource NumTbVm}, Path=NumTbText, UpdateSourceTrigger=PropertyChanged}"/> 
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>



<Style TargetType="{x:Type local:ErrMsgGui}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:ErrMsgGui}">
                <TextBlock Text="{ Binding  Source={StaticResource val}, Path=ErrMsgGuiText, UpdateSourceTrigger=PropertyChanged}" Background="{TemplateBinding Background}"/>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Validations.cs:

    private const string ONLY_NUMBERS_REGEX = @"^[0-9]+$";  //Nur Zahlen

    private string _ErrMsgGuiText;
    public string ErrMsgGuiText
    {
        get { return _ErrMsgGuiText; }
        set
        {
            _ErrMsgGuiText = value;
            Debug.Print("QueryText: " + value);
            OnPropertyChanged("ErrMsgGuiText"); 
        }
    }


    public object[] onlyNumbers(string s2c, bool output)
    {
        object[] objRes = new object[2];
        bool result = true;
        string errMsg = ""; 

        Regex regex = new Regex(ONLY_NUMBERS_REGEX);

        if (s2c != null && s2c != "" && !regex.IsMatch(s2c)) 
        {
            result = false;
            errMsg = "Nur Zahlen sind zulässig";
        }

        objRes[0] = result;
        objRes[1] = errMsg;

        if (output == true) 
        { 
           ErrMsgGuiText = errMsg;

        }  
         return objRes;
    }

    public void onlyNumbers(string s2c)
    {
        onlyNumbers(s2c, true);
    }

    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

    #endregion

    protected void OnPropertyChanged(string prop)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(prop));

        }

    }

NumTbViewModel.cs:

    Validations val = null;

    public NumTbViewModel() 
    {
        val = new Validations(); 
    }

    private string _NumTbText;
    public string NumTbText 
    {
        get { return _NumTbText; }
        set 
        {
            _NumTbText = value;
            this.OnPropertyChanged("NumTbText");
            val.onlyNumbers(_NumTbText);

        }
    }

    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

    #endregion

    protected void OnPropertyChanged(string prop)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(prop));

        }

    }

1 个答案:

答案 0 :(得分:0)

看起来TextBlock源正在查看Validations类的静态资源,而NumTbViewModel中调用的Validations与静态资源不同。解决方案可以是向NumTbViewModel.cs添加属性并将绑定指向该属性,以使Validations类实例相同。在NumTbViewModel.cs中添加:

Validations _val;
    public Validations Val
    {
        get { return _val; }
        set 
        {
            _val = value;
            this.OnPropertyChanged("Val");
        }
    }

在TextBlock上的xaml绑定中更改源和路径:

<TextBlock Text="{ Binding  Source={StaticResource NumTbVm}, Path=Val.ErrMsgGuiText, UpdateSourceTrigger=PropertyChanged}" Background="{TemplateBinding Background}"/>

另一种方式: 您可以在定义静态资源时设置NumTbViewModel的Val属性,如下所示:

<local:Validations x:Key="val" />
<local:NumTbViewModel x:Key="NumTbVm" Val="{StaticResource val}" />

这样做可以保留原来的绑定。