有段代码看不明白。大侠帮忙看看

[goodb515344oy]

我在单击btnAdd的时候，出现了错误。提示说_Insertting为空。为什么会这样能？
要怎么改这段代码？

private void btnAdd_Click(object sender, EventArgs e)
{
int Index=1;
double x, y;
OnInsertPoint(Index, x, y);
}
private void OnInsertPoint(int index, double x, double y)
{
FlightPoint point = new FlightPoint();
point.X = x;
point.Y = y;
FlightPointCollectionEventArgs e = new FlightPointCollectionEventArgs(index, point, null);
_Insertting(this, e);
}
private FlightPointCollectionEventHandler _Insertting;
public event FlightPointCollectionEventHandler Insertting
{
add
{
_Insertting = (FlightPointCollectionEventHandler)Delegate.Combine(_Insertting, value);
}
remove
{
_Insertting = (FlightPointCollectionEventHandler)Delegate.Remove(_Insertting, value);
}
}
public delegate void FlightPointCollectionEventHandler(object sender,
FlightPointCollectionEventArgs e);

[feiyun0112]

Insertting(this, e);


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[贫僧又回来了]

[Quote=引用 1 楼 feiyun0112 的回复:]
Insertting(this, e);


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[/Quote]
只有引用的内容不允许回复！！

[xxyping]

你那里面有很多的方法都没贴出来,看的不怎么明白,自己设个段点慢慢的看看吧

[文飞扬]

private void btnAdd_Click(object sender, EventArgs e) 
        { 
            int Index=1; 
            double x, y; 
            OnInsertPoint(Index, x, y); //这里没有对变量xy赋值啊，肯定出错了
        } 

[j1a2b3c]

是不是没有订阅事件？

[gogogo]

        public event FlightPointCollectionEventHandler Insertting 
        { 
            add 
            { 
                _Insertting = (FlightPointCollectionEventHandler)Delegate.Combine(_Insertting, value); 
            } 
            remove 
            { 
                _Insertting = (FlightPointCollectionEventHandler)Delegate.Remove(_Insertting, value); 
            } 

这句应该是属性Insertting 的定义，外部没有对Insertting 赋值就先调用了OnInsertPoint方法，所以出错

[starts_2000]

private void OnInsertPoint(int index, double x, double y) 
        { 
            FlightPoint point = new FlightPoint(); 
            point.X = x; 
            point.Y = y; 
            FlightPointCollectionEventArgs e = new FlightPointCollectionEventArgs(index, point, null); 
            if(_Insertting ! = null)
               _Insertting(this, e); 
        } 

[zccmy22]

恩。入参给值。看一下。

[killer_liqiao]

up

[hangang7403]

ding

[花落_]

[Quote=引用 6 楼 gogogo 的回复:]
C# code public event FlightPointCollectionEventHandler Insertting
{
add
{
_Insertting = (FlightPointCollectionEventHandler)Delegate.Combine(_Insertting, value);
}
remove
{
_Insertting = (FlightPointCollectionEventHandler)Delegate.Remove(_Insertting, value);
}
…
[/Quote]
支持

[gogogo]

private void btnAdd_Click(object sender, EventArgs e) 
        { 
            int Index=1; 
            double x, y; 
            if(_Insertting != null)
                OnInsertPoint(Index, x, y); 
        } 

或者这么改

[goodb515344oy]

gogogo
我就是不知道_Insertting 要怎么用，为什么是null的，我试过用两个testbox给x,y输入数值；
int index = 1;
int x, y;
x = int.Parse(txtLong.Text);
y = int.Parse(txtLat.Text);
OnInsertPoint(index, x, y);
但是还是不行，运行到 _Insertting(this, e)就出错了， _Insertting为null.
要如何让 _Insertting(this, e)不会出错呢？？

[gogogo]

改成我12楼的代码

[dlmeijianyu]

顶下。