如何在Xamarin.Forms中设置控件的宽度

Question

我试图在iPad应用程序的Xamarin.Forms中调整文本框[Entry]控件的宽度和高度,但它没有使用WidthRequest属性设置宽度.

任何人都可以帮助我同样如何设置控件的宽度.

这是我的XAML代码,使用Grid和StackLayout,但没有一个工作.

<Grid VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" >
    <Grid.RowDefinitions>
    <RowDefinition Height="Auto"  ></RowDefinition>
    <RowDefinition Height="*"></RowDefinition>
    <RowDefinition Height="10"></RowDefinition>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
    <ColumnDefinition Width="*"></ColumnDefinition>
    </Grid.ColumnDefinitions>

    <Image Grid.Row="0" Grid.Column="0" Source="loginlogo.png"></Image>
    <StackLayout Grid.Row="1" Grid.Column="0">
    <Entry Placeholder="Enter Username" WidthRequest="20"></Entry>
    <Entry Placeholder="Enter Password" WidthRequest="20"></Entry>
    <Button Text="Button 1"></Button>
    </StackLayout>
    </Grid>

还尝试使用Stack Layout

<StackLayout Spacing="10">
    <Entry x:Name="txtUserName" Placeholder="Enter Username" WidthRequest="2" HeightRequest="200"></Entry>
    <Entry x:Name="txtPassword" Placeholder="Enter Password" WidthRequest="2" HeightRequest="200"></Entry>
    <Button Text="Button 1"></Button></StackLayout>

Answer 1

请注意,您必须使用WidthRequest指定Horizo​​ntalOptions才能使其在StackLayout上运行,因为默认情况下它将尝试自动展开.

下面显示的StackLayout示例: -

        StackLayout objStackLayout = new StackLayout()
        {
            Spacing = 10
        };
        //
        Entry objEntry1 = new Entry()
        {
            Placeholder = "Enter Username",
            WidthRequest = 300,
            HeightRequest = 200,
            HorizontalOptions = LayoutOptions.Start
        };
        objStackLayout.Children.Add(objEntry1);
        //
        Entry objEntry2 = new Entry()
        {
            Placeholder = "Enter Password",
            WidthRequest = 200,
            HeightRequest = 200,
            HorizontalOptions = LayoutOptions.Start
        };
        objStackLayout.Children.Add(objEntry2);
        //
        Button objButton1 = new Button()
        {
            Text = "Button1",
            HorizontalOptions = LayoutOptions.Start
        };
        objStackLayout.Children.Add(objButton1);

Answer 2

使用StackLayout间距,水平/垂直选项和填充的组合.例:

<StackLayout Padding="20" Spacing="10">
  <Entry Placeholder="Username"
         VerticalOptions="Start"
         HorizontalOptions="FillAndExpand" />

  <Entry Placeholder="Password"
         VerticalOptions="Start"
         HorizontalOptions="FillAndExpand" />

  <Button Text="Submit" VerticalOptions="EndAndExpand" />
</StackLayout>