C# 验证文本框以仅允许数字值
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Validating a textbox to allow only numeric values
提问by Wizard
Possible Duplicate:
How do I make a textbox that only accepts numbers?
可能的重复：
如何制作只接受数字的文本框？
I have a phone number that I wish to store as a string.
我有一个电话号码，希望将其存储为字符串。
I read this in using
我在使用中读到了这个
txtHomePhone.Text
What I think I need is some kind of is numeric but can't get it working
我认为我需要的是某种数字但无法使其正常工作
if (txtHomePhone.Text == //something.IsNumeric)
{
//Display error
}
else
{
//Carry on with the rest of program ie. Add Phone number to program.
}
What is the best way to allow only numeric values to be entered?
只允许输入数值的最佳方法是什么？
采纳答案by Picrofo Software
Since txtHomePhonerepresents a TextBox, you may use the KeyPressevent to accept the characters you would like to allow and reject what you would not like to allow in txtHomePhone
由于txtHomePhone代表 a TextBox，您可以使用该KeyPress事件接受您希望允许的字符并拒绝您不希望允许的字符txtHomePhone
Example
例子
public Form1()
{
InitializeComponent();
txtHomePhone.KeyPress += new KeyPressEventHandler(txtHomePhone_KeyPress);
}
private void txtHomePhone_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar >= '0' && e.KeyChar <= '9' || e.KeyChar == '') //The character represents a backspace
{
e.Handled = false; //Do not reject the input
}
else
{
e.Handled = true; //Reject the input
}
}
Notice: The following character (which is not visible) represents a backspace.
Notice: You may always allow or disallow a particular character using e.Handled.
Notice: You may create a conditional statement if you would like to use -, , (or )only once. I would recommend you to use Regular Expressions if you would like to allow these characters to be entered in a specific position.
注意：以下字符（不可见）表示退格。
注意：您始终可以使用 来允许或禁止特定字符e.Handled。
注意：如果您想使用、或仅使用一次-，您可以创建一个条件语句。如果您希望允许在特定位置输入这些字符，我建议您使用正则表达式。()
Example
例子
if (e.KeyChar >= '0' && e.KeyChar <= '9' || e.KeyChar == '') //The character represents a backspace
{
e.Handled = false; //Do not reject the input
}
else
{
if (e.KeyChar == ')' && !txtHomePhone.Text.Contains(")"))
{
e.Handled = false; //Do not reject the input
}
else if (e.KeyChar == '(' && !txtHomePhone.Text.Contains("("))
{
e.Handled = false; //Do not reject the input
}
else if (e.KeyChar == '-' && !textBox1.Text.Contains("-"))
{
e.Handled = false; //Do not reject the input
}
else if (e.KeyChar == ' ' && !txtHomePhone.Text.Contains(" "))
{
e.Handled = false; //Do not reject the input
}
else
{
e.Handled = true;
}
}
Thanks,
I hope you find this helpful :)
谢谢，
我希望你觉得这有帮助:)
回答by Blachshma
Try this
尝试这个
if (!txtHomePhone.Text.All(c=> Char.IsNumber(c)))
{
//Display error
}
else
{
//Carry on with the rest of program ie. Add Phone number to program.
}
回答by Dave New
To check to see if a numeric value has been entered, you can use Integer.TryParse
要检查是否已输入数值，您可以使用 Integer.TryParse
int num;
bool isNum = Integer.TryParse(txtHomePhone.Text.Trim(), out num);
if (!isNum)
//Display error
else
//Carry on with the rest of program ie. Add Phone number to program.
BUT remember that telephone numbers aren't necessarily only numeric. Refer to Trevor Pilley answer for a masked textbox.
但请记住，电话号码不一定只是数字。有关蒙面文本框，请参阅 Trevor Pilley 的答案。
回答by Trevor Pilley
I'm assuming that you are using Windows Forms here, have a look at the MaskedTextBox. It allows you to specify an input mask of characters.
我假设您在这里使用 Windows 窗体，请查看MaskedTextBox。它允许您指定字符的输入掩码。
txtHomePhone.Mask = "##### ### ###";
Since this allows you to restrict the input values, you can safely parse the value to an integer.
由于这允许您限制输入值，因此您可以安全地将值解析为整数。
Note: If you are using WPF, I don't think there is a MaskedTextBox in the base libraries, however there are extensions available on NuGetwhich may provide similar functionality.
注意：如果您使用 WPF，我认为基础库中没有 MaskedTextBox，但是NuGet上有可用的扩展，它们可能提供类似的功能。
回答by Mike Rodey
Usually I would use Integer.TryParse as davenewza recommended, but another alternative is to use the VisualBasic IsNumeric function from C#.
通常我会像 davenewza 推荐的那样使用 Integer.TryParse，但另一种选择是使用 C# 中的 VisualBasic IsNumeric 函数。
Add a reference to the Microsoft.VisualBasic.dll file and then use the following code.
添加对 Microsoft.VisualBasic.dll 文件的引用，然后使用以下代码。
if (Microsoft.VisualBasic.Information.IsNumeric(txtHomePhone.Text))
{
//Display error
}
else
{
//Carry on with the rest of program ie. Add Phone number to program.
}
回答by Wizard
The best way I've found to do this is to only allow the user to enter the numeric keys into the text box, thanks for your help.
我发现最好的方法是只允许用户在文本框中输入数字键，感谢您的帮助。
