C#实现字母与ASCII码互相转换

string P_str_temp ="abc";
Encoding P_encoding =Encoding.GetEncoding("unicode");
byte[]P_byte =P_encoding.GetBytes(P_str_temp);
string P_str=P_byte[0].ToString();

// 字符与ASCII相互转换
using System.Text;
 
namespace _036
{
    public partial class Form1 : Form
    {
        private GroupBox? groupBox1;
        private Button? button2;
        private Button? button1;
        private TextBox? textBox1;
        private TextBox? textBox2;
        private TextBox? textBox3;
        private TextBox? textBox4;
 
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
 
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // button2
            // 
            button2 = new Button
            {
                Location = new Point(117, 58),
                Name = "button2",
                Size = new Size(91, 23),
                TabIndex = 6,
                Text = "ASCII转字符",
                UseVisualStyleBackColor = true
            };
            button2.Click += Button2_Click;
            // 
            // button1
            // 
            button1 = new Button
            {
                Location = new Point(117, 29),
                Name = "button1",
                Size = new Size(91, 23),
                TabIndex = 5,
                Text = "字符转ASCII",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // textBox1
            // 
            textBox1 = new TextBox
            {
                Location = new Point(6, 29),
                Name = "textBox1",
                Size = new Size(100, 23),
                TabIndex = 1
            };
            // 
            // textBox2
            // 
            textBox2 = new TextBox
            {
                Location = new Point(219, 29),
                Name = "textBox2",
                Size = new Size(100, 23),
                TabIndex = 2
            };
            // 
            // textBox3
            // 
            textBox3 = new TextBox
            {
                Location = new Point(6, 58),
                Name = "textBox3",
                Size = new Size(100, 23),
                TabIndex = 3
            };
            // 
            // textBox4
            // 
            textBox4 = new TextBox
            {
                Location = new Point(219, 58),
                Name = "textBox4",
                Size = new Size(100, 23),
                TabIndex = 4
            };
            // 
            // groupBox1
            // 
            groupBox1 = new GroupBox
            {
                Location = new Point(12, 14),
                Name = "groupBox1",
                Size = new Size(325, 100),
                TabIndex = 0,
                TabStop = false,
                Text = "字符与ASCII相互转换"
            };
            groupBox1.Controls.Add(button2);
            groupBox1.Controls.Add(button1);
            groupBox1.Controls.Add(textBox1);
            groupBox1.Controls.Add(textBox2);
            groupBox1.Controls.Add(textBox3);
            groupBox1.Controls.Add(textBox4);
            groupBox1.SuspendLayout();
            
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(349, 126);
            Controls.Add(groupBox1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "字符与ASCII互转";           
            groupBox1.ResumeLayout(false);
            groupBox1.PerformLayout();           
        }
 
        /// <summary>
        /// 字母转ASCII
        /// 注释掉的部分异常：
        /// Index was outside of the bounds of the array
        /// 未处理的异常：System.IndexOutOfRangeException：索引超出数组的范围(在第一个if语句处)
        /// 修改后，正常了
        /// </summary>
        private void Button1_Click(object? sender, EventArgs e)
        {
            if (textBox1!.Text != string.Empty)                 //判断输入是否为空
            {
                /*if (Encoding.GetEncoding("unicode").          //判断输入是否为字符
                     GetBytes(new char[] { textBox2!.Text[0] })[1] == 0)  */             
                if (char.IsLetterOrDigit(textBox1.Text.ToCharArray()[0])) //判断输入是否为字符
                {
                    textBox2!.Text = Encoding.GetEncoding(      //字符转ASCII码
                        "unicode").GetBytes(textBox1.Text)[0].ToString();
                }
                else
                {
                    textBox2!.Text = string.Empty;              //输出空字符串
                    MessageBox.Show("请输入字母！", "提示！");//提示用户信息
                }
            }
            else
            {               
                MessageBox.Show("请输入字母！", "提示！");
            }
        }
 
        /// <summary>
        /// ASCII转字母
        /// </summary>
        private void Button2_Click(object? sender, EventArgs e)
        {
            if (textBox3!.Text != string.Empty)             //判断输入是否为空
            {
                if (int.TryParse(                           //将输入的字符转换为数字
                   textBox3.Text, out int P_int_Num))
                {
                    textBox4!.Text =
                        ((char)P_int_Num).ToString();       //ASCII码转为字符
                }
                else
                {
                    MessageBox.Show(                        //如果输入不符合要求弹出提示框
                        "请输入正确ASCII码值。", "错误！");
                }
            }
            else
            {
                MessageBox.Show("请输入ASCII！", "提示！"); 
            }          
        }
    }
}