winform 开发 label是固定值 要乘 textBox内的值应该怎么写？

label是固定值（可以是整数也可以是小数）

×

textBox内输入的值（必须是整数）

=

label

label1.text = label.text × textbox.text

public partial class Form1 : Form
    {
        private vm _vm;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            _vm = new vm(){A=24.2m};
           
            this.label1.DataBindings.Add(nameof(Label.Text), _vm, nameof(vm.A));
            this.textBox1.DataBindings.Add(nameof(TextBox.Text), _vm, nameof(vm.B));
            this.label2.DataBindings.Add(nameof(Label.Text), _vm, nameof(vm.C));

            this.textBox1.KeyPress += TextBox1_KeyPress;
            this.textBox1.TextChanged += TextBox1_TextChanged;
            
        }

        private void TextBox1_TextChanged(object? sender, EventArgs e)
        {
           this.textBox1.DataBindings[0].WriteValue();
        }

        private void TextBox1_KeyPress(object? sender, KeyPressEventArgs e)
        {
            if ((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8)
            {
                e.Handled = true;
            }
        }
    }

    public class vm:INotifyPropertyChanged
    {
        private decimal _a;
        private int _b;

        public decimal A
        {
            get => _a;
            set
            {
                if (value == _a) return;
                _a = value;
                OnPropertyChanged();
            }
        }

        public int  B
        {
            get => _b;
            set
            {
                if (value == _b) return;
                _b = value;
                OnPropertyChanged();
            }
        }

        public decimal C => A * (decimal)B;

        public event PropertyChangedEventHandler? PropertyChanged;

        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }