C ++ Builder XE8上的TEdit输入验证 [英] TEdit Input Validation on C++ Builder XE8

问题描述

我是C ++ Builder XE8的新手。

I am very new to C++ Builder XE8.

我希望必须输入的最小和最大数字长度最多为六个数字，我也需要确保只输入数字（0为例外），而不输入字母字符，退格键，标点符号等。

I want the minimum and maximum length of numbers that must be typed is as much as six numbers, also I need to make sure that only number is entered (0 is exception), and not an alphabetic character, backspace, punctuation, etc.

我还要生成一个错误框如果输入了除数字以外的其他任何内容。

I would also like to produce an error box if anything other than a number is entered.

我尝试了几种代码组合，下面可以看到其中三种，但是这些代码都不起作用。

I've tried a few combinations of codes, three of which can be seen below, but none of those codes works.

任何帮助都将不胜感激！

Any help would sure be appreciated!

（1）。

void __fastcall TForm1::Edit1KeyPress(TObject *Sender, System::WideChar &Key)
{
  Edit1->MaxLength = 6;

  if (!((int)Key == 1-9)) {
  ShowMessage("Please enter numerals only");
  Key = 0;
  }
}

（2）。

void __fastcall TForm1::Edit1KeyPress(TObject *Sender, System::WideChar &Key)
{
  Edit1->MaxLength = 6;

  if (Key <1 && Key >9) {
  ShowMessage("Please enter numerals only");
  Key = 0;
  }
}

（3）。

void __fastcall TForm1::Edit1KeyPress(TObject *Sender, System::WideChar &Key)
{
  Edit1->MaxLength = 6;

  if( Key == VK_BACK )
   return;

  if( (Key >= 1) && (Key <= 9) )
   {
  if(Edit1->Text.Pos(1-9) != 1 )
   ShowMessage("Please enter numerals only");
   Key = 1;
  return;
  }
}

推荐答案

TEdit 具有 NumbersOnly 属性：

TEdit has a NumbersOnly property:

仅允许将数字键入文本编辑。

Allows only numbers to be typed into the text edit.

将其设置为true，然后让操作系统为您处理验证。但是，如果您要手动验证它，请使用以下命令：

Set it to true and let the OS handle the validation for you. But, if you want to validate it manually, use this:

void __fastcall TForm1::Edit1KeyPress(TObject *Sender, System::WideChar &Key)
{
    // set this at design-time, or at least
    // in the Form's constructor. It does not
    // belong here...
    //Edit1->MaxLength = 6;

    if( Key == VK_BACK )
        return;

    if( (Key < L'0') || (Key > L'9') )
    {
        ShowMessage("Please enter numerals only");
        Key = 0;
    }
}

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