將文本框限制爲1位小數。 Winform C＃

Question

我正在開發一個使用c＃的winform應用程序我已經成功實現了一種將文本框限制爲兩位小數的方法。我怎樣才能做到一位小數。 ？ 。

我爲小數點後兩位碼\

private void txtHraRep_KeyPress(object sender, KeyPressEventArgs e) 
     { 
      if (char.IsNumber(e.KeyChar) || e.KeyChar == '.') 
      { 
       if (Regex.IsMatch(
       txtHraRep.Text, 
       "^\\d*\\.\\d{2}$")) e.Handled = true; 
      } 
      else e.Handled = e.KeyChar != (char)Keys.Back; 
     } 

更改爲 「^ \ d * \ \ d {1} $」））e.Handled = TRUE;

輸出

Answer 1

你可以只檢查其中小數點分隔符是在你的文本，然後確保比字符串的長度小於2（小數點後一位做這沒有正則表達式地方和1少陣列長度）

var decSeparator = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator; 
var idx = txtBasic.Text.IndexOf(decSeparator); 
if(idx + 2 >= txtBasic.Text.Length) 
    ... 

Answer 2

代替使用TextBox控制爲輸入的，看看使用MaskedTextbox共爲你的輸入而戰。這將減輕對輸入的任何自我驗證，並且可以向用戶顯示關於爲什麼他們的輸入不正確的消息可以期望他們的輸入。

約MaskedTextBox控件的更多信息：
MaskedTextbox
MaskedTextbox.Mask property
MSDN Walkthrough: Working with the MaskedTextBox Control

Answer 3

我只是想

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
    { 
     { 
      if (char.IsNumber(e.KeyChar) || e.KeyChar == '.') 
      { 
       if (Regex.IsMatch(
       textBox1.Text, 
       "^\\d*\\.\\d{1}$")) e.Handled = true; 
      } 
      else e.Handled = e.KeyChar != (char)Keys.Back; 
     } 
    } 

和它的工作，因爲它應該。它將輸入限制在小數點後的一位數字。 但是，您可以輸入多個小數點，然後輸入更多數字。 所以，你可以嘗試

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
    { 
     if (char.IsNumber(e.KeyChar) || ((e.KeyChar == '.') && (textBox1.Text.IndexOf('.')== -1))) 
     { 
      if (Regex.IsMatch(
       textBox1.Text, 
       "^\\d*\\.\\d{1}$")) e.Handled = true; 
     } 
     else e.Handled = e.KeyChar != (char)Keys.Back; 
    } 

或類似

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
    { 
     if (char.IsNumber(e.KeyChar) || ((e.KeyChar == '.') && (textBox1.Text.IndexOf('.')== -1))) 
     { 
      if (textBox1.Text.IndexOf('.') > 0) 
      { 
       if (textBox1.Text.IndexOf('.') < textBox1.Text.Length - 1) 
        e.Handled = true; 
      } 
     } 
     else e.Handled = e.KeyChar != (char)Keys.Back; 
    } 

Answer 4

創建一個新的文本框繼承的TextBox像

[DefaultBindingProperty("Text")] 
[DefaultProperty("Text")] 
[DefaultEvent("ValueChanged")] 
public class SpecializedTextBox : TextBox 
{ 
    private bool _allowNegativeSign = false; 
    public bool AllowNegativeSign 
    { 
     get { return _allowNegativeSign; } 
     set { _allowNegativeSign = value; } 
    } 
    public decimal? DecimalValue 
    { 
     get 
     { 
      decimal k; 
      if (decimal.TryParse(this.Text, out k)) 
       return k; 
      else 
       return null; 
     } 
     set 
     { 
      if (value.HasValue) 
       this.Text = value.Value.ToString(); 
      else 
       this.Text = ""; 
     } 
    } 
    private void This_TextChanged(object sender, EventArgs e) 
    { 
     string s = base.Text; 
     int cursorpos = base.SelectionStart; 
     bool separatorfound = false; 
      for (int i = 0; i < s.Length;) 
      { 
       if (char.IsNumber(s[i])) 
        i++; 
       else if (AllowNegativeSign && i < System.Globalization.CultureInfo.CurrentUICulture.NumberFormat.NegativeSign.Length && s.StartsWith(System.Globalization.CultureInfo.CurrentUICulture.NumberFormat.NegativeSign)) 
        i++; 
       else if (!separatorfound && s[i].ToString() == System.Threading.Thread.CurrentThread.CurrentCulture.NumberFormat.NumberDecimalSeparator) 
       { 
        separatorfound = true; 
        i++; 
       } 
       else 
       { 
        s = s.Remove(i, 1); 
        if (i < cursorpos) 
         cursorpos--; 
       } 
      } 
     if (base.Text != s) 
     { 
      base.Text = s; 
      base.SelectionStart = cursorpos; 
      base.SelectionLength = 0; 
     } 
     if (ValueChanged != null) 
      ValueChanged(this, EventArgs.Empty); 
    } 
    public event EventHandler ValueChanged; 

    private void InitializeComponent() 
    { 
     this.SuspendLayout(); 
     // 
     // SpecializedTextBox 
     // 
     this.TextChanged += new System.EventHandler(this.This_TextChanged); 
     this.ResumeLayout(false); 
    } 
    public SpecializedTextBox() 
     : base() 
    { 
     InitializeComponent(); 
    } 
} 

現在使用這個文本框，並使用DecimalValue設置或獲取您的價值

Answer 5

嘗試：

List<string> doubleList = new List<string>(new string[] 
     { 
      "12345", 
      "1234.5", 
      "123.45", 
      "12.345", 
      "1.2345", 
      "1.2", 
      "1.23", 
      "1.234", 
      "1.23.45", 
      "12.3", 
      "123.4", 
     }) { }; 

    private void button1_Click(object sender, EventArgs e) 
    { 
     foreach (var x in doubleList) 
     { 
      int countNumber = Regex.Matches(x, @"[0-9]").Count; 
      int countOfDot = Regex.Matches(x, @"\.").Count; 

      if (countOfDot == 1 && countNumber != 0) //contains "." and any digit 
      { 
       Console.WriteLine(x); 
      } 
      else if (countOfDot == 0 && countNumber != 0) //not contains "." and any digit 
      { 
       Console.WriteLine(x); 
      } 
      else 
      { 
       //do nothing . . . 
      } 
     } 
    } 

輸出：

all except for **1.23.45** (2dots)