将保存值或字符串，但是未保存主页本身选择器上的选择。当我重新打开应用程序时，选择器为空。我不知道如何使用选择器的语法。
npicker1 = nlocation1;
xaml：
<Picker x:Name="drainlocationPicker1" Title="Drain Location"
Grid.Column="1" SelectedIndexChanged="drain1Handle_SelectedIndexChanged" />
//后面的代码
//选择列表：
public SettingsPage()
{
InitializeComponent();
nquantity();
list = new List<string>();
list.Add("Right1");
list.Add("Right2");
list.Add("Right3");
list.Add("Right4");
//picker1 example selection
void n1Handle_SelectedIndexChanged(object sender, System.EventArgs e)
{
nlocation1 = (string)nlocationPicker1.SelectedItem;
//if picker1 is not empty then show n2picker
if (nlocationPicker1.SelectedItem != null)
{
nPicker2.IsVisible = true;
Picker1.IsEnabled = false;
nlocationPicker2.Items.Remove((string)nlocationPicker1.SelectedItem);
nlocationPicker3.Items.Remove((string)nlocationPicker1.SelectedItem);
}
//supposed to save picker selection
void settingsaveButton_Clicked(object sender, System.EventArgs e)
{
bool isNameEmpty = string.IsNullOrEmpty(nameEntry.Text);
if (isNameEmpty == true)
{
DisplayAlert("Enter Name", "PLEASE", "OK");
}
else if (nlocationPicker1.SelectedIndex == -1)
{
DisplayAlert("Error1", "Please select your country.", "Ok");
nPicker1.Focus();
}
else
{
Navigation.PushModalAsync(new HomePage());
//put nlocation1 to nPicker1
// npicker=nlocation1???
Settings.n1LocationSettings = nlocation1;
Settings.n2LocationSettings = nlocation2;
Settings.n3LocationSettings = nlocation3;
}
答案 0 :(得分：0)
如果要为选择器设置默认值，则可以使用：
1。function sendEmails() {
var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Agent Report - Monthly")
var startRow = 3; // First row of data to process since there is a header row
var emailRange = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Agent Report - Monthly").getRange("D3");
var emailAddress = emailRange.getValues();
var chartImg = Charts.newLineChart.setRange(12, 8) //This Throws an error
var subject = "Agent Report - Monthly"; // This is the subject of the email
var greeting_text = 'Hey Please find the below Report '+'</b><br><br>';
var text = greeting_text;
text+=SheetConverter.convertRange2html(sheet.getRange(startRow, 3 ,10,8));
text+='<br>';
var options = {
htmlBody: text,
noReply:true
};
MailApp.sendEmail({
to: "xxx@der.com",
subject: subject,
htmlBody: options,
inlineImages: {
chartImg: chartImage,
}
});
}
2。设置索引：ChartImg
3。在xaml中：
npicker.SelectedItem = nlocation1;注意：
可以通过设置选择器来初始化选择器以显示特定项目 SelectedIndex或SelectedItem属性。但是，这些属性 必须在初始化ItemsSource集合之后设置。
文档在这里：picker
我不知道您的项目中的npicker.SelectedIndex = 2;是什么。我为您创建了一个简单的示例。
在xaml中：
<Picker x:Name="drainlocationPicker1"
Title="Drain Location"
HorizontalOptions="CenterAndExpand"
VerticalOptions="CenterAndExpand"
ItemsSource="{Binding myList}"
ItemDisplayBinding="{Binding Title}"
SelectedItem="{Binding SelectedObject}"
/>
在后面的代码中：
Settings.Drain1LocationSettings您可以使用<StackLayout>
<!-- Place new controls here -->
<Picker x:Name="drainlocationPicker1" Title="Drain Location" SelectedIndexChanged="DrainlocationPicker1_SelectedIndexChanged" VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand"/>
</StackLayout>
存储用户选择的值，并在下次将其设置为选择器。
通过使用plugin.setting，您应通过以下方式定义public partial class MainPage : ContentPage
{
private static ISettings AppSettings => CrossSettings.Current;
public static string LastPickValue
{
get => AppSettings.GetValueOrDefault(nameof(LastPickValue), string.Empty);
set => AppSettings.AddOrUpdateValue(nameof(LastPickValue), value);
}
public MainPage()
{
InitializeComponent();
List<string> list = new List<string>();
list.Add("Right1");
list.Add("Right2");
list.Add("Right3");
list.Add("Right4");
drainlocationPicker1.ItemsSource = list;
//Set the default value
drainlocationPicker1.SelectedItem = LastPickValue;
}
private void DrainlocationPicker1_SelectedIndexChanged(object sender, EventArgs e)
{
string nlocation1 = (string)drainlocationPicker1.SelectedItem;
LastPickValue = nlocation1;
}
}
：
LastPickValue我上传了示例here，您可以检查它，让我知道它是否有效。