在屏幕鍵盤上使用正則表達式

Question

好吧，我真的陷入了這裏傢伙：/。我有一個（自定義！）屏幕鍵盤，我想使用正則表達式。

I成功創建了一個正則表達式，只允許0-9和comma作爲普通鍵盤。

當然，這不適用於我的屏幕鍵盤。

我有一個代碼段工程...

但我也有一個空格鍵，退格鍵和2個鍵四處移動。

當我使用正則表達式如下代碼，並單擊空格，空格鍵或插入符號按鈕我得到這個錯誤：

Object reference not set to an instance of an object. 

我在做什麼錯？

// the regex code 
    private Control keyb = null; 
    private void EditProdPriceEx_GotFocus(object sender, RoutedEventArgs e) 
    { 
     string AllowedChars = "[^0-9,]"; 
     if (Regex.IsMatch(EditProdPriceEx.Text, AllowedChars)) 
     { 
      keyb = (Control)sender; 
     } 
    } 

空格鍵：

private void KnopSpatie_Click(object sender, RoutedEventArgs e) 
    { 
     TextBox tb = keyb as TextBox; 
     int selStart = tb.SelectionStart; // here is where i get the error 
     string before = tb.Text.Substring(0, selStart); 
     string after = tb.Text.Substring(before.Length); 
     tb.Text = string.Concat(before, " ", after); 
     tb.SelectionStart = before.Length + 1; 
    } 

退格鍵：

private void KnopWissen_Click(object sender, RoutedEventArgs e) 
    { 
     TextBox tb = keyb as TextBox; 
     int cursorPosition = tb.SelectionStart; // here is where i get the error 
     if (cursorPosition > 0) 
     { 
      tb.Text = tb.Text.Substring(0, cursorPosition -1) + tb.Text.Substring(cursorPosition); 
      tb.SelectionStart = cursorPosition - 1; 
     } 
    } 

移動插入符左鍵：

private void KnopLinks_Click(object sender, RoutedEventArgs e) 
    { 
     TextBox tb = keyb as TextBox; 
     if (tb.SelectionStart > 0) // here is where i get the error 
     { 
      int selStart = tb.SelectionStart; 
      string before = tb.Text.Substring(0, selStart); 
      string after = tb.Text.Substring(before.Length); 
      tb.SelectionStart = before.Length - 1; 
     } 
    } 

移動插入符號右移按鈕：

private void KnopRechts_Click(object sender, RoutedEventArgs e) 
    { 
     TextBox tb = keyb as TextBox; 

     if (tb.SelectionStart >= 0) // here is where i get the error 
     { 
      int selStart = tb.SelectionStart; 
      string before = tb.Text.Substring(0, selStart); 
      string after = tb.Text.Substring(before.Length); 
      tb.SelectionStart = before.Length + 1; 
     } 
    } 

Answer 1

我想你一定要試試這個。在第一個代碼中。

// the regex code 
private Control keyb = null; 
private void EditProdPriceEx_GotFocus(object sender, RoutedEventArgs e) 
{ 
    string AllowedChars = "[^0-9,]"; 
    if (Regex.IsMatch(EditProdPriceEx.Text, AllowedChars)) 
    { 
     keyb = (Control)sender; 
    } 
} 

你讓KEYB空，而不是由你提到的任意鍵（空格等），我認爲這不產生錯誤設定的基準設定。你能檢查一下嗎？