小编Cin*_*ing的帖子

我一直在寻找如何处理一对多关系的日子.但我无法理解它.

我正在开发一个存储主题成绩的应用程序.因此,一个主题与成绩有很多关系.所有数据当前都存储在一个数组中.

var vakken: [(naam:String, voorkeurGemiddelde:Double, wegingGemiddelde:Double, cijfer:[Double], weging:[Double], gemiddelde:Double)] = []
其中[Double]的 - Cijfer和weging-是等级的属性.

我目前有以下用于保存数据:

 let context = AppDelegate().managedObjectContext

    // Create subject
    let entitySubject = NSEntityDescription.entityForName("Subject", inManagedObjectContext: context)
    let Subject = NSManagedObject(entity: entitySubject!, insertIntoManagedObjectContext: context)

    // Populate subject
    Subject.setValue(vakken.last!.naam, forKey: "name")
    Subject.setValue(vakken.last!.voorkeurGemiddelde, forKey: "voorkeurGemiddelde")
    Subject.setValue(vakken.last!.wegingGemiddelde, forKey: "wegingNP")
    Subject.setValue(vakken.last!.gemiddelde, forKey: "gemiddelde")

    for var j = 0; j < vakken.last!.cijfer.count-1; j++ {

        let Grade = NSEntityDescription.insertNewObjectForEntityForName("Grade", inManagedObjectContext: context)

        Grade.setValue(vakken.last!.cijfer[j], forKey: "cijfer")
        Grade.setValue(vakken.last!.weging[j], forKey: "weging")

        Subject.setValue(NSSet(object: Grade), forKey: "grade")
    }

    do{
        try …

我有一个带有项目列表的xamarin选择器,我想在iPhone上按下"完成"按钮并在android上按下"Oke"按钮时删除选择器.
我有删除选择器的代码.但我不知道可能由哪个event_Handler.

码:

Picker picker = new Picker
    {
        Title = "What's in the slot?",
        VerticalOptions = LayoutOptions.CenterAndExpand
        //HorizontalOptions = LayoutOptions.Center 

    };

private void Displaypickerview(int row, int column)
    {
        if (status == "filling board")
        {
            foreach (string text in pickerText)
            {


picker.Items.Add(text);
        }
        foreach (string ore in oreLevels)
        {
            picker.Items.Add(ore);
        }


        picker.SelectedIndexChanged += (sender, args) =>
        {
            if (picker.SelectedIndex == -1)
            {

            }
            else
            {
                //change value of cell and button
                Picker picker = (Picker)sender;
                int index = picker.SelectedIndex;

                if …

标题已经解释了.从nsfetchedresultscontroller删除缓存的swift代码是什么？

这是我得到的错误:

You have illegally mutated the NSFetchedResultsController's fetch request, its predicate, or its sort descriptor without either disabling caching or using +deleteCacheWithName:'

和代码:

if arranged == "naam - A-Z" {
            let sortDescriptor = NSSortDescriptor(key: "name", ascending: true)
            self.fetchedResultsController.fetchRequest.sortDescriptors = [sortDescriptor]
        }else if arranged == "naam - Z-A" {
            let sortDescriptor = NSSortDescriptor(key: "name", ascending: false)
            self.fetchedResultsController.fetchRequest.sortDescriptors = [sortDescriptor]
        }else if arranged == "gemiddelde - 1-10" {
            let sortDescriptor = NSSortDescriptor(key: "gemiddelde", ascending: true)
            self.fetchedResultsController.fetchRequest.sortDescriptors = [sortDescriptor]
        }else if arranged …

我找不到问题的答案：Can you have an array as value in a lua table?

local colors = {"blue" = {0,0,1,1}, "green" = {0,1,0,1}, "red" = {1,0,0,1} , "orange" = {0.5, 0, 0.5, 1}, "black" = {0,0,0,1}, "gold" = {1, 215/255, 0, 1}}

我使用 corona sdk 在这一行收到错误：

'}' 预计位于 '=' 附近

我的屏幕上有一个按钮,当我按下按钮时,我想要一个选择器显示一个项目列表,当选择一个项目时,按钮的文本应该更改为那个,选择器应该消失.

这是我的代码:

Picker picker = new Picker
    {
        Title = "What's in the slot?",
        VerticalOptions = LayoutOptions.CenterAndExpand
        //HorizontalOptions = LayoutOptions.Center 

    };

按下按钮时调用的函数:

private void Displaypickerview(int row, int column)
    {
        if (status == "filling board")
        {
            foreach (string text in pickerText)
            {
                picker.Items.Add(text);
            }
            foreach (string ore in oreLevels)
            {
                picker.Items.Add(ore);
            }


            picker.SelectedIndexChanged += (sender, args) =>
            {
                if (picker.SelectedIndex == -1)
                {

                }
                else
                {
                    //change value of cell and button
                    Picker picker = (Picker)sender;
                    int index = picker.SelectedIndex;

                    if …

所以我最近将 xcode 更新到 8.0，现在有了 swift 3。
随着新的更新，nsfetchedresultcontroller 发生了一些变化。
经过大量的搜索和尝试，我又开始工作了。
但是我仍然有删除缓存（）函数的错误

这是我的原始代码：

NSFetchedResultsController.deleteCache(withName: "Master")

但我收到此错误：

/Users/Camiel/Documents/Schoolcijfer/NeededNumber/Magister2,0/VakkenTableViewController.swift:208:36: Type 'String?' does not conform to protocol 'ExpressibleByStringLiteral'

任何帮助表示赞赏。

我正在使用xamarin表单的网格,当点击网格按钮时我有一个事件处理程序按钮我不知道如何知道按钮在哪一行和哪一行.

这是我的网格代码:

<Grid x:Name="grid" ColumnSpacing="6" RowSpacing="5" RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Constant=-20}"
                RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent,
                         Property=Height,
                         Factor=0.50 }">

<Grid.RowDefinitions>
  <RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
    <Button x:Name="button1" Text="1" Grid.Row="0" Grid.Column="0" Clicked="handle_clicked"/>
    <Button x:Name="button2" Text="2" Grid.Row="0" Grid.Column="1" Clicked="handle_clicked"/>
    <Button x:Name="button3" Text="3" Grid.Row="0" Grid.Column="2" Clicked="handle_clicked"/>
    <Button x:Name="button4" Text="4" Grid.Row="0" Grid.Column="3" Clicked="handle_clicked"/>
    <Button x:Name="button5" Text="5" Grid.Row="0" Grid.Column="4" Clicked="handle_clicked"/>
    <Button x:Name="button6" Text="6" Grid.Row="0" Grid.Column="5" Clicked="handle_clicked"/>

    <Button x:Name="button7" Text="7" Grid.Row="1" Grid.Column="0" Clicked="handle_clicked"/>
    <Button x:Name="button8" Text="8" Grid.Row="1" Grid.Column="1" …