Question

我有一个文本框，用户输入一个数字，但我怎么能这样做，如果他们输入'。'在它之后它只允许2位小数？

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
{ 
    if (!char.IsControl(e.KeyChar)  
        && !char.IsDigit(e.KeyChar)  
        && e.KeyChar != '.') 
    { 
        e.Handled = true; 
    } 

    // only allow one decimal point 
    if (e.KeyChar == '.'  
        && (sender as TextBox).Text.IndexOf('.') > -1) 
    { 
        e.Handled = true; 
    } 
}

Answer 1

只需添加：

if (Regex.IsMatch(textBox1.Text, @"\.\d\d")) {
   e.Handled = true;
}

到你的功能结束

Answer 2

只是想指出接受的答案将不允许您在符合条件后输入小数点前的任何数字。

其他当前示例都不会起作用，因为它们没有获得光标位置

如果您仍想使用按键事件，可以按如下方式重新计算代码：

string senderText = (sender as TextBox).Text;
string senderName = (sender as TextBox).Name;
string[] splitByDecimal = senderText.Split('.');
int cursorPosition = (sender as TextBox).SelectionStart;

if (!char.IsControl(e.KeyChar) 
    && !char.IsDigit(e.KeyChar) 
    && (e.KeyChar != '.'))
{
    e.Handled = true;
}


if (e.KeyChar == '.' 
    && senderText.IndexOf('.') > -1 )
{
    e.Handled = true;
}


if (!char.IsControl(e.KeyChar) 
    && senderText.IndexOf('.') < cursorPosition 
    && splitByDecimal.Length > 1 
    && splitByDecimal[1].Length == 2)
{
    e.Handled = true;
}

或者，使用TextChanged事件并执行以下操作，它将起作用：

string enteredText = (sender as TextBox).Text;
int cursorPosition = (sender as TextBox).SelectionStart;

string[] splitByDecimal = enteredText.Split('.');

if(splitByDecimal.Length > 1 && splitByDecimal[1].Length > 2){
    (sender as TextBox).Text = enteredText.Remove(enteredText.Length-1);
    (sender as TextBox).SelectionStart = cursorPosition - 1;
}

Answer 3

string word=txtPrice.Text.Trim();
string[] wordArr=word.Split('.');
if(wordArr.Length>1)
{
   string afterDot=wordArr[1];
   if(afterDot.Length>2)
   {
    alert("Only 2 allowed");
    txtPrice.Text=wordArr[0]+"."+afterDot.SubString(0,2);  
   } 
}

Answer 4

我相信MaskedTextBox类可以帮助你。

此处有更多信息：https://msdn.microsoft.com/en-us/library/system.windows.forms.maskedtextbox(v=vs.110).aspx

如果它不适合您的情况，您可以随时为自己编写验证和/或自定义控件。

以下是数字文本框的示例： http://msdn.microsoft.com/en-us/library/ms229644(v=vs.80).aspx#Y0

Answer 5

namespace WindowsFormsApplication10
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        label1.Text = "";
        double no;
        no = double.Parse(textBox1.Text);

        string[] ones = new string[19] {"one ","two ","three ","four ","five ","six ","seven ","eight ","nine ","ten ","eleven ","twele ",
                                        "thiten ","fourten ","fiften ","sixten ","seventeen ","eighteen ", "ninteen "};
        string[] tens = new string[9] { "ten ", "twenty ", "thirty ", "fourty ", "fifty ", "sixty ", "seventy ", "eighty ", "ninty " };

        int i=0;




        if (no > 999 & no < 100000)
        {
            i = (int)no / 1000;
            if (i < 20)
                label1.Text = label1.Text + ones[i - 1] + "";
            else if (i > 20)
            {
                int r = 0;
                r = i % 10;
                i = i / 10;
                label1.Text = label1.Text + tens[i - 1] + "";
                label1.Text = label1.Text + ones[r - 1] + "";

            }

            label1.Text = label1.Text + "thousand ";
            no = no % 1000;
        }

        if (no > 99 & no < 1000)
        {
            i = (int)no / 100;
            label1.Text = label1.Text + ones[i - 1] + "hundred ";
            no = no % 100;
        }
        if (no > 19 & no < 99)
        {
            i = (int)no / 10;
            label1.Text = label1.Text + tens[i - 1];
            no = no % 10;
        }
        if (no > 0 & no < 20)
        {
            label1.Text = label1.Text + ones[(int)no-1] + " ";
        }
        label1.Text = label1.Text + "Rupees ";


    }

    private void button2_Click(object sender, EventArgs e)
    {
        textBox1.Text = "";
        label1.Text = "";
        textBox1.Focus();

    }

    private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {

        if (!char.IsControl(e.KeyChar)
     && !char.IsDigit(e.KeyChar)
     && e.KeyChar != '.')
        {
            e.Handled = true;
        }

        // only allow one decimal point 
        if (e.KeyChar == '.'
            && (sender as TextBox).Text.IndexOf('.') > -1)
        {
            e.Handled = true;
        }
        string word = textBox1.Text.Trim();
        string[] wordArr = word.Split('.');
        if (wordArr.Length > 1)
        {
            string afterDot = wordArr[1];
            if (afterDot.Length > 1)
            {

                e.Handled = true;
            }
        }

    }
}
}

这是您需要的程序。

Answer 6

我正在个人使用它，它不是很优雅，但是就像一个魅力。该脚本限制用户仅使用数字字符，仅1个点，仅2个十进制数字和空格。

因此可接受的输入将类似于：1.22，2135.25，3535.5等。

void Decimal(object sender, KeyPressEventArgs Event) {
            Event.Handled = true;
            bool FalseInput = !char.IsControl(Event.KeyChar) && !char.IsDigit(Event.KeyChar) && !char.IsControl(Event.KeyChar) && Event.KeyChar != 8 && Event.KeyChar != '.';
            if (!FalseInput){
                Event.Handled = false;
                if (Regex.IsMatch(FreightTextBox.Text, @"^\d+\.\d*$") && Event.KeyChar != 8) {
                    bool ContainDot = FreightTextBox.Text.Contains(".");
                    Event.Handled = true;
                    if (ContainDot && Event.KeyChar != 8 && Event.KeyChar!='.'){
                        Event.Handled = Regex.IsMatch(FreightTextBox.Text, @"\.\d\d");
                    }
                }
            }
        }

Answer 7

要解决上面的Casperah评论，您可以更改条件以处理控制字符，并允许编辑选择文本。

if (!char.IsControl(e.KeyChar) 
    && Regex.IsMatch(textBox1.Text, @"\.\d\d")
    && String.IsNullOrWhiteSpace(textBox1.SelectedText))
{
    e.Handled = true;
}

文本框中只允许小数点后两位数字？

7 个答案: