如何解决这个错误：类型的未处理的异常“System.NullReferenceException”发生在DotTeach.exe [英] how do i fix this error :An unhandled exception of type 'System.NullReferenceException' occurred in DotTeach.exe

问题描述

更多信息：未设置为一个对象的实例对象引用

Additional information: Object reference not set to an instance of an object.

我有这样的代码

DotTeachDataSet ds;
DotTeachDataSetTableAdapters.QuestionsTableAdapter ta;

private void button1_Click(object sender, RoutedEventArgs e)
{                                         
    ta.CreateQuestion(discussionQuestion.Text, webPage.Text, choiceA.Text, choiceB.Text, choiceC.Text, choiceD.Text, hint.Text, rightAnswerCbox.Uid);
    ta.Fill(ds.Questions);
}

这是即时通讯使用，试图得到一个XAML从文本框中的值和它们发送到数据的基础上，但我不断收到错误：

That Im using to try to get the values from text boxes in a xaml and send them to a data base but I keep getting the error:

型
未处理的异常'System.NullReferenceException'
发生在DotTeach.exe

An unhandled exception of type 'System.NullReferenceException' occurred in DotTeach.exe

更多信息：对象
引用不设置到
对象的实例

Additional information: Object reference not set to an instance of an object.

和Visual Studio中突出了行

and visual studio highlights the line

ta.CreateQuestion(discussionQuestion.Text, webPage.Text, choiceA.Text, choiceB.Text, choiceC.Text, choiceD.Text, hint.Text, rightAnswerCbox.Uid);

有没有人有任何想法我可以尝试？

Does anyone have any ideas what i could try?

我摆脱了错误信息，但它仍然没有做什么，我需要做的。我试图让按钮被点击时，将数据添加到数据库中。继承人我用不工作

I got rid of the error message but it's still not doing what I need it to do. I'm trying to get it to add data to a database when the button is clicked. Heres the function I'm using thats not working

private void button1_Click(object sender, RoutedEventArgs e)
    {
        DotTeach.DotTeachDataSet dotTeachDataSet = ((DotTeach.DotTeachDataSet)(this.FindResource("dotTeachDataSet")));
        DotTeach.DotTeachDataSetTableAdapters.QuestionsTableAdapter dotTeachDataSetQuestionsTableAdapter = new DotTeach.DotTeachDataSetTableAdapters.QuestionsTableAdapter();


        //ADD THE QUESTION TO THE DATA BASE
        dotTeachDataSetQuestionsTableAdapter.CreateQuestion(discussionQuestion.Text, webPage.Text, choiceA.Text, choiceB.Text, choiceC.Text, choiceD.Text, hint.Text, rightAnswer.Text);
    }

我甚至不知道什么尝试。

I'm not even sure what else to try.

推荐答案

好，要获得的NullReferenceException ，有一个的的下面是空：

Well, to get a NullReferenceException, one of the following is null:

• TA


• discussionQuestion


• 网页


• choiceA


• choiceB


• choiceC


• choiceD


• 提示


• rightAnswerCbox

• ta
• discussionQuestion
• webPage
• choiceA
• choiceB
• choiceC
• choiceD
• hint
• rightAnswerCbox

我的猜的是 TA ，但你应该能够找到出去要么记录或调试器。什么是意味着要指定一个非空值 TA ？

My guess would be ta, but you should be able to find that out either with logging or in the debugger. What's meant to be assigning a non-null value to ta?

这是总是失败（在这种情况下，它会很容易诊断），或者只是偶尔？

Is this always failing (in which case it'll be easy to diagnose) or only sometimes?

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