如何在数据绑定的上下文中将值从一个页面传递到另一个页面？ [英] How to pass value from one page to another page in the context of data binding?
问题描述
MainPage.xaml
< TextBlock Tap =TextBlock_TapText ={Binding LineOne}TextWrapping =NoWrapStyle ={StaticResource PhoneTextExtraLargeStyle}/ >
MainPage.xaml.cs （当用户点击建筑名称，它将导航到新页面）
public void TextBlock_Tap（object sender，System.Windows.Input.GestureEventArgs e）
{
var building =（（TextBlock）sender）.Text; //获取基于轻敲建筑物的信息
//根据有关轻敲的建筑物的信息执行操作
if（building ==Thomas Gosnell Hall）
{
//MessageBox.Show(\"08 - （GOS））;
NavigationService.Navigate（new Uri（/ MapLocation.xaml？building =+ building，UriKind.Relative））; //通过Uri参数
}
将字符串值传递给目标页面$ else else（建筑==Lyndon Baines Johnson Hall）
{
MessageBox.Show（060 - （LBJ））;
}
}
MapLocation.xaml
< TextBlock x：Name =buildingNameText =Building NameMargin =9，-7 ，0,0Style ={StaticResource PhoneTextTitle1Style}/>
MapLocation.xaml.cs （用户选择的新页面建筑名称）
/ **
*如何：创建绑定（代码后面）
*来源：http://msdn.microsoft.com/en-us/library/cc838207%28v=vs.95%29.aspx?cs-save-lang=1&cs-lang=csharp#code-snippet-1
* /
//定义源对象
public class Building
{
public string BuildingName {get;组; }
}
public MapLocation（）
{
InitializeComponent（）;
加载+ = MapLocation_Loaded;
/ * //创建源对象的实例
构建bldg = new Building（）;
bldg.BuildingName = building; //根据用户的点击更改值
//创建绑定对象
绑定MyBinding = new Binding（）;
//设置绑定对象上的绑定属性
MyBinding.Path = new PropertyPath（BuildingName）;
MyBinding.Mode = BindingMode.OneTime
//通过设置DataContext属性设置绑定的源
buildingName.DataContext = bldg;
//将绑定绑定到FrameworkElement的
buildingName.SetBinding（TextBlock.TextProperty，MyBinding）; * /
}
private void MapLocation_Loaded（object sender，RoutedEventArgs e）
{
// throw new NotImplementedException（）;
字符串构建;
if（NavigationContext.QueryString.TryGetValue（building，out building））
{
//根据建筑参数值加载信息
buildingName.Text = building;
}
}
/ * public MapLocation_Loaded（）
{
string building;
if（NavigationContext.QueryString.TryGetValue（building，out building））
{
//根据建筑参数值加载信息
}
} * /
问题在于这一行 bldg.BuildingName = building; ，因为它表示名称构建在当前上下文中不存在。它存在于MainPage.xaml.cs中，但不存在于MapLocation.xaml.cs中。我的数据如何绑定建筑名称取决于用户的敲门砖选择下一页？
我建议通过 Uri 参数传递字符串值到目标页面：
public void TextBlock_Tap（object sender，System.Windows.Input.GestureEventArgs e）
{
var building =（（TextBlock）sender）.Text;
NavigationService.Navigate（new Uri（/ MapLocation.xaml？building =+ building，UriKind.Relative））;
}
然后在目标页面中处理加载正确的信息，例如页面加载事件处理程序：
public MapLocation_Loaded（）
{
字符串构建;
if（NavigationContext.QueryString.TryGetValue（building，out building））
{
//根据建筑参数值加载信息
}
}
I am creating an app where we have a Data Template list of building names and when clicked on say "Thomas Gosnell Hall", it will go to a new page with the TextBlock changed to that of the selected building name "Thomas Gosnell Hall". I know data binding is used to do this, but how do I do it across two different pages?
MainPage.xaml
<TextBlock Tap="TextBlock_Tap" Text="{Binding LineOne}" TextWrapping="NoWrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
MainPage.xaml.cs (When a user taps on the building name, it will navigate to new page)
public void TextBlock_Tap(object sender, System.Windows.Input.GestureEventArgs e)
{
var building = ((TextBlock)sender).Text; // gets information based on the tapped building
//perform action based on information about the tapped building
if(building == "Thomas Gosnell Hall")
{
//MessageBox.Show("08 - (GOS)");
NavigationService.Navigate(new Uri("/MapLocation.xaml?building=" + building, UriKind.Relative)); // pass the string value to destination page through Uri parameter
}
else if(building == "Lyndon Baines Johnson Hall")
{
MessageBox.Show("060 - (LBJ)");
}
}
MapLocation.xaml
<TextBlock x:Name="buildingName" Text="Building Name" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
MapLocation.xaml.cs (The new page after the user selected the building name)
/**
* How to: Create the Binding (behind code)
* Source: http://msdn.microsoft.com/en-us/library/cc838207%28v=vs.95%29.aspx?cs-save-lang=1&cs-lang=csharp#code-snippet-1
*/
// Define source object
public class Building
{
public string BuildingName { get; set; }
}
public MapLocation()
{
InitializeComponent();
Loaded += MapLocation_Loaded;
/* // create an instance of the source object
Building bldg = new Building();
bldg.BuildingName = building; // value to change depending on user's click
// create a binding object
Binding MyBinding = new Binding();
// set the binding properties on the binding object
MyBinding.Path = new PropertyPath("BuildingName");
MyBinding.Mode = BindingMode.OneTime;
// set the source of the binding by setting the DataContext property
buildingName.DataContext = bldg;
// attach the binding to the property of the FrameworkElement
buildingName.SetBinding(TextBlock.TextProperty, MyBinding);*/
}
private void MapLocation_Loaded(object sender, RoutedEventArgs e)
{
//throw new NotImplementedException();
string building;
if(NavigationContext.QueryString.TryGetValue("building", out building))
{
//load information based on building parameter value
buildingName.Text = building;
}
}
/*public MapLocation_Loaded()
{
string building;
if(NavigationContext.QueryString.TryGetValue("building", out building))
{
//load information based on building parameter value
}
}*/
The problem lies within this line bldg.BuildingName = building; as it says The name building does not exist in the current context. It exists in the MainPage.xaml.cs, but not in MapLocation.xaml.cs. How do I data bind the building name depending on the user's tapped choice of building onto the next page?
I would suggest to pass the string value to destination page through Uri parameter :
public void TextBlock_Tap(object sender, System.Windows.Input.GestureEventArgs e)
{
var building = ((TextBlock)sender).Text;
NavigationService.Navigate(new Uri("/MapLocation.xaml?building=" + building, UriKind.Relative));
}
Then handle loading correct informations in the destination page, for example in page Loaded event handler :
public MapLocation_Loaded()
{
string building;
if(NavigationContext.QueryString.TryGetValue("building", out building))
{
//load information based on building parameter value
}
}
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