CEdit数字验证事件C ++ MFC [英] CEdit numeric validation event C++ MFC
问题描述
请输入正整数。
这是情况:
1.我有一个数字(说20)在框中。
2.我删除该号码。
3.我得到错误对话框。
有没有人可以告诉我如何拦截这个事件并在其中放一个默认值?
这里是我的属性窗格的样子:
const int DEFAULT_VALUE = 20;
class MyPropertyPane:public CPropertyPane
{
// ....
private:
CEdit m_NumericBox;
int m_value;
// ....
public:
afx_msg void OnEnChangeNumericBox();
// ....
}
void MyPropertyPane :: MyPropertyPane()
{
//设置默认值
m_value = DEFAULT_VALUE;
}
// ....
void MyPropertyPane :: DoDataExchange(CDataExchange * pDX)
{
DDX_Control(pDX,IDC_NUMERIC_BOX,m_NumericBox) ;
//将显示的值设置为20
DDX_Text(pDX,IDC_NUMERIC_BOX,m_value);
}
// ....
void MyPropertyPane :: OnEnChangeNumericBox()
{
//有人删除了框中的值,得到一个事件
//表示该值已更改。
//我尝试通过更新我的数据从框中获取值
UpdateData(TRUE);
// m_value仍然是20,虽然该值是
//在文本框内删除。
}
您正在接收来自数据验证例程,而不是数据交换例程。在DoDataExchange()中可能会有一个这样的调用:
void MyPropertyPane :: DoDataExchange(CDataExchange * pDX)
{
DDX_Control(pDX,IDC_NUMERIC_BOX,m_NumericBox);
DDX_Text(pDX,IDC_NUMERIC_BOX,m_value);
DDV_MinMaxInt(pDX,m_value,1,20); //如果m_value中的值超出范围1-20,MFC会弹出一个错误对话框
}
您可以通过删除内置的MFC数据验证并添加自己的方法来解决此问题:
void MyPropertyPane :: DoDataExchange(CDataExchange * pDX)
{
DDX_Control(pDX,IDC_NUMERIC_BOX,m_NumericBox);
DDX_Text(pDX,IDC_NUMERIC_BOX,m_value);
if(m_value< 1 || m_value> 20)
{
m_value = DefaultValue;
}
}
I have a CEdit text box which is a part of a property pane and only allows numeric values (positive integers). The box works fine when people enter non-numeric values, but when they delete the value in the box a dialog pops up saying: "Please enter a positive integer."
Here is the situation:
1. I have a number (say 20) in the box.
2. I delete the number.
3. I get the error dialog.
Could anybody tell me how I can intercept this event and put a default value in there?
Here is what my property pane looks like:
const int DEFAULT_VALUE = 20;
class MyPropertyPane:public CPropertyPane
{
//....
private:
CEdit m_NumericBox;
int m_value;
//....
public:
afx_msg void OnEnChangeNumericBox();
//....
}
void MyPropertyPane::MyPropertyPane()
{
// Set a default value
m_value = DEFAULT_VALUE;
}
//....
void MyPropertyPane::DoDataExchange(CDataExchange* pDX)
{
DDX_Control(pDX, IDC_NUMERIC_BOX, m_NumericBox);
// this sets the displayed value to 20
DDX_Text(pDX, IDC_NUMERIC_BOX, m_value);
}
//....
void MyPropertyPane::OnEnChangeNumericBox()
{
// Somebody deleted the value in the box and I got an event
// saying that the value is changed.
// I try to get the value from the box by updating my data
UpdateData(TRUE);
// m_value is still 20 although the value is
// deleted inside the text box.
}
The message you are receiving is coming from the data validation routines, not the data exchange routines. There is probably a call like this in DoDataExchange():
void MyPropertyPane::DoDataExchange(CDataExchange* pDX)
{
DDX_Control(pDX, IDC_NUMERIC_BOX, m_NumericBox);
DDX_Text(pDX, IDC_NUMERIC_BOX, m_value);
DDV_MinMaxInt(pDX, m_value, 1, 20); // if the value in m_value is outside the range 1-20, MFC will pop up an error dialog
}
You can fix this problem by removing the built-in MFC data validation and adding your own:
void MyPropertyPane::DoDataExchange(CDataExchange* pDX)
{
DDX_Control(pDX, IDC_NUMERIC_BOX, m_NumericBox);
DDX_Text(pDX, IDC_NUMERIC_BOX, m_value);
if( m_value < 1 || m_value > 20 )
{
m_value = DefaultValue;
}
}
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