如何在Xamarin.Forms中设置控件的宽度

Question

我尝试在Xamarin.Forms的iPad应用中调整文本框[Entry]控件的宽度和高度，但使用WidthRequest属性并不能设置宽度。

有人能否帮助我解决如何设置控件宽度的问题。

以下是我使用Grid和StackLayout的XAML代码，但它们都没有起作用。

<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>

也尝试使用堆栈布局

<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>

- Nirav Mehta

Answer 1

注意，在 StackLayout 上默认会尝试自动扩展，因此您需要使用 WidthRequest 指定 HorizontalOptions 才能使其正常工作。

以下是适用于 StackLayout 的示例：

        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);

- Pete

Answer 2

使用StackLayout结合间距，水平/垂直选项和内边距。示例：

<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>

- Sergey Metlov