Question

我正在探索如何使用Django，我在我的Django应用程序中创建了两个模型。

public void DetectKeyboard()
        {           

            AttemptKeyboardDetection:
            try
            {
                AttachThreadInput(GetWindowThreadProcessId(GetForegroundWindow(), IntPtr.Zero), GetCurrentThreadId(), true);
                IntPtr focus = GetFocus();
                AttachThreadInput(GetWindowThreadProcessId(GetForegroundWindow(), IntPtr.Zero), GetCurrentThreadId(), false);
                if (GetClassName(focus, this.StringBuilder, this.StringBuilder.Capacity))
                {
                    ActiveProcessFocus = this.StringBuilder.ToString();
                    Debug.WriteLine("Active Process: " + ActiveProcessFocus);
                    if ((PreviousProcessFocus != ActiveProcessFocus) && !ActiveProcessFocus.Contains("KeyboardOpener"))
                    {
                        Debug.WriteLine("Checking if editing...");
                        if ((((ActiveProcessFocus == "Edit") || (ActiveProcessFocus == "SearchPane")) || (ActiveProcessFocus.Contains("RichEdit") || ActiveProcessFocus.Contains("SearchEdit"))) || ((ActiveProcessFocus.Contains("TextfieldEdit") || ActiveProcessFocus.Contains("Afx:00400000")) || (((ActiveProcessFocus == "_WwG") || (ActiveProcessFocus == "Scintilla")) || (ActiveProcessFocus == "SPEAD0C4"))))
                        {
                            Debug.WriteLine("Editing! Opening keyboard...");
                            try
                            {
                                ProcessStartInfo startInfo = new ProcessStartInfo(@"C:\Program Files\Common Files\Microsoft Shared\ink\TabTip.exe");
                                startInfo.WindowStyle = ProcessWindowStyle.Hidden;
                                Process.Start(startInfo);
                            }
                            catch
                            {
                            }
                        }
                        else
                        {
                            try
                            {
                                SendMessage(FindWindow("IPTip_Main_Window", null), 0x112, (IntPtr) 0xf060, IntPtr.Zero);
                                foreach (Process process in Process.GetProcessesByName("osk"))
                                {
                                    process.Kill();
                                }
                            }
                            catch
                            {
                            }
                        }
                        PreviousProcessFocus = ActiveProcessFocus;
                    }
                }
                Thread.Sleep(250);
                goto AttemptKeyboardDetection;
            }
            catch
            {
                goto AttemptKeyboardDetection;
            }
        }

        [DllImport("user32.dll")]
        private static extern IntPtr AttachThreadInput(IntPtr AttachId, IntPtr AttachToId, bool AttachStatus);
        [DllImport("user32.dll")]
        private static extern bool GetClassName(IntPtr hWnd, StringBuilder ClassName, int ClassMax);
        [DllImport("kernel32.dll")]
        private static extern IntPtr GetCurrentThreadId();
        [DllImport("user32.dll")]
        private static extern IntPtr GetFocus();
        [DllImport("user32.dll")]
        private static extern IntPtr GetForegroundWindow();
        [DllImport("user32.dll")]
        private static extern IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ThreadId);
        [DllImport("user32.dll")]
        private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

第一个模型是人，第二个模型是技能。现在关系如何，每个人都会有很多技能。

现在我可以用数据更新数据库，网站的管理部分也可以正常工作。

在Django Shell上，我尝试运行命令：

from django.db import models

#first model
class Person(models.Model):
    name = models.CharField(max_length=40)
    email = models.CharField(max_length=100)
    title = models.CharField(max_length=100)
    image = models.CharField(max_length=200)

    def __str__(self):
         return self.name

#second model
class Skill(models.Model):
    person = models.ForeignKey(Person)
    skill = models.CharField(max_length=60)
    years = models.CharField(max_length=40)

    def __str__(self):
        return self.skill, self.person

我得到的是以下错误：

Skill.object.all()

或者如果我尝试命令：

Traceback (most recent call last):

File "<console>", line 1, in <module>
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\query.py", line 235, in __repr__
    return '<QuerySet %r>' % data
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\base.py", line 572, in __repr__
    u = six.text_type(self)
TypeError: __str__ returned non-string (type tuple)

我得到：

Skill.objects.get(pk=1)

但是，如果我运行如下命令：

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\base.py", line 572, in __repr__
    u = six.text_type(self)
TypeError: __str__ returned non-string (type tuple)

我得到了具有“Photoshop”技能的人的名字。

我想知道我在这里做错了什么;也许我不应该用这种方式用外键查询表？或许我做错了什么。

嗯，最后我想查询的是，我想找到具有给定名称或主键的人的所有技能。

Answer 1

__str__应返回str。所以改变这样的事情

return self.skill, self.person

到

return "%s-%s" %(self.skill, self.person.name)

Answer 2

您的__str__方法返回一个元组（self.skill，self.person），它必须返回那些对象的str表示。为了实现这一目标，请更改：

return self.skill, self.person

到

return "{}, {}".format(self.skill, self.person)

查询Django表中具有一对多关系的相关字段

2 个答案: