如何使用MVVM对文本框进行事件处理 [英] How to do Event Handling of text boxes using MVVM

问题描述

  private   void  txtUsername_LostFocus（对象发​​件人，RoutedEventArgs e）
 {
  string  usergrouptxt = txtUsername.Text; 
 尝试 
 {
  if （ string  .IsNullOrEmpty（usergrouptxt））
 {
 txtUsername.BorderBrush =  new  SolidColorBrush（Colors.Red）; 
} 
 其他 
 {
 
} 
} 
  catch （SqlException usrgrpexc）
 {
 MessageBox.Show（usrgrpexc.ToString（））; 
} 
 
} 

我该怎么做我在MVVM中的ViewModel中的上述操作？

解决方案

轻松借助 MVVM Light Toolkit 。来自Blend SDK的S ystem.Windows.Interactivity 。

只需添加此命名空间：

 xmlns：i =clr-namespace：System.Windows.Interactivity; assembly = System.Windows.Interactivity
 xmlns：cmd =clr-namespace：GalaSoft.MvvmLight.Command; assembly = GalaSoft.MvvmLight .Extras

然后，在你的 TextBox XAML注入下一行：

 <   textbox     x：name   =  txt1    ....   =     xmlns：x   = ＃unknown >  
 <   i：interaction.triggers     xmlns：i   = ＃unknown >  
 <   i：eventtrigger     eventname   =  LostFocus >  
 <   cmd：eventtocommand     command   =  {Binding TestCommand，< br mode =    hold   =  /> Mode = OneWay}    xmlns：cmd   = ＃unknown >  
 CommandParameter ={Binding Text， 
 ElementName = txt1，
 Mode = OneWay}
 MustToggleIsEnabledValue =True/> 
 <  < span class =code-leadattribute> / cmd：eventtocommand  >  <  < span class =code-leadattribute> / i：eventtrigger  >  
 <   / i：interaction.triggers  >  
 <   / textbox  >  

private void txtUsername_LostFocus(object sender, RoutedEventArgs e)
        {
            string usergrouptxt = txtUsername.Text;
            try
            {
                if (string.IsNullOrEmpty(usergrouptxt))
                {
                    txtUsername.BorderBrush = new SolidColorBrush(Colors.Red);
                }
                else
                {

                }
            }
            catch (SqlException usrgrpexc)
            {
                MessageBox.Show(usrgrpexc.ToString());
            }

        }

How can I do the above operation in my ViewModel in MVVM?

解决方案

Easily with help of MVVM Light Toolkit. and System.Windows.Interactivity from Blend SDK.
Just add this namespaces:

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras"

and then, in your TextBox XAML inject next lines:

<textbox x:name="txt1" ....="" xmlns:x="#unknown">
    <i:interaction.triggers xmlns:i="#unknown">
        <i:eventtrigger eventname="LostFocus">
            <cmd:eventtocommand command="{Binding TestCommand,<br mode=" hold=" />                                          Mode=OneWay}" xmlns:cmd="#unknown">
               CommandParameter="{Binding Text,
                                  ElementName=txt1,
                                  Mode=OneWay}"
               MustToggleIsEnabledValue="True" />
        </cmd:eventtocommand></i:eventtrigger>
    </i:interaction.triggers>
</textbox>

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