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创建用下划线替换空格的WPF文本框的最佳方法是什么?

wpf-controls textbox wpf c#

Greg D · 技术社区 · 14 年前

我正在创造一个 FilteredTextBox 在wpf中,将包含的 TextBox 控制。这个 文本框过滤器 必须只允许范围内的字符 [a-zA-Z0-9_] 要进入,我已经有相当多的工作。我已经迷上了 OnPreviewTextInput 要处理键入的字符, OnPreviewDrop 为了过滤拖放的字符,我添加了一个PreviewExecutedHandler,它在每次对控件执行命令以处理粘贴时都会运行。

到目前为止,一切都很好。

棘手的是,控件在键入空格时还应使用下划线替换空格。

我已经想出了一个解决方案,但它感觉被很好地拼凑在一起,我不知道它遗漏了什么。我觉得必须有一种更好的技术,我只是不知道。我所做的一切:

internal class FilteredTextBox : TextBox
{
    public FilteredTextBox()
    {
        CommandManager.AddPreviewExecutedHandler(this, this.HandlePreviewExecuteHandler);
    }

    private void HandlePreviewExecuteHandler(object sender, ExecutedRoutedEventArgs e)
    {
        var uiCmd = e.Command as RoutedUICommand;
        if (uiCmd != null && (uiCmd.Text == "Space" || uiCmd.Text == "ShiftSpace"))
        {
            // We're manually handling spaces, so we need to make appropriate checks.
            if (this.Text.Length == this.MaxLength) return;

            if (this.SelectionLength == 0)
            {
                // If the user is just typing a space normally
                // We need to cache CaretIndex b/c it's reset to 0 when we set Text.
                var tmpIndex = this.CaretIndex;
                this.Text = this.Text.Insert(tmpIndex, "_");
                this.CaretIndex = tmpIndex + 1;
            }
            else
            {
                // Otherwise, replace the selected text with the underscore and fixup the caret.
                this.SelectedText = "_";
                this.CaretIndex += this.SelectedText.Length;
                this.SelectionLength = 0;
            }

            e.Handled = true; // If someone hits the spacebar, say we handled it.
            return;
        }
    }
}

有更聪明的方法吗?

3 回复 | 直到 13 年前

Robert Rossney 14 年前

OnPreviewKeyDown

bufferz 14 年前

TextBox ValueConverter

public class SpaceConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return System.Convert.ToString(value); 
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            string text = System.Convert.ToString(value);

            //the meat and potatoes is this line
            text = text.Replace(" ", "_");    

            return text;
        }
    }

<TextBox Text="{Binding Path=UserString, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource SpaceConverter}}" />

UserString DataContext

SpaceConverter UserControl

<UserControl.Resources>
   <local:SpaceConverter x:Key="SpaceConverter" />
</UserControl.Resources>

local

Viv 14 年前