using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace TextBox_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.PasswordChar = '@'; //設置文本框的PasswordChar屬性為字符@
            textBox2.UseSystemPasswordChar = true;
            //設置文本框的UseSystemPasswordChar屬性為True;
        }

        private void label1_Click(object sender, EventArgs e)
        {

        }
    }
}
    

program.cs:

      using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace TextBox_1
{
    static class Program
    {
        /// <summary>
        /// 應用程序的主入口點。
        /// </summary>
        [STAThread]
        static void Main()
        {
            //Enabled 獲取或設置一個值,該值指示控件能否夠對用戶交互做出響應
            //ForeColor:獲取或設置控件的前景色
            //Modifiers:指示TextBox控件的可見性級別
            //Multiline://獲取或設置字符,該字符用于
            //PasswordChar:獲取或設置字符
            //                          :public char PasswordChar{get; set;}
            //ReadOnly:獲取或設置一個值,該值指示文本框中的文本是否為僅僅讀
            //               :public bool ReadOnly{get ; set; }
            //               :TextBox.ReadOnly=true;  將文本設置為僅僅讀
            //RightToLeft:獲取或設置一個值.該值指示是否將控件的元素對齊以支持使用從右向左的字體區域設置
            //ScrollBars:獲取或設置哪些滾動欄應出如今多行TextBox控件中
            //Text:獲取或設置TextBox控件的文本
            //UseSystemPasswordChar:獲取或設置一個值,該值指示TextBox控件中的文本是否應該以默認的password字符顯示
            //                                              :public Bool UseSystemPasswordChar{get ;set ;}
            //Visible:獲取或設置一個值,該值指示是否顯示該控件及其全部父控件
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());

        }
    }
}

    

Form設計:

      namespace TextBox_1
{
    partial class Form1
    {
        /// <summary>
        /// 必需的設計器變量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理全部正在使用的資源。
        /// </summary>
        /// <param name="disposing">假設應釋放托管資源，為 true。否則為 false。
      

      
      

        </param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗口設計器生成的代碼

        /// <summary>
        /// 設計器支持所需的方法 - 不要
        /// 使用代碼編輯器改動此方法的內容。
        /// </summary>
        private void InitializeComponent()
        {
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(155, 27);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(121, 21);
            this.textBox1.TabIndex = 0;
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(155, 77);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(121, 21);
            this.textBox2.TabIndex = 1;
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(66, 30);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(83, 12);
            this.label1.TabIndex = 2;
            this.label1.Text = "PassWordChar:";
            this.label1.Click += new System.EventHandler(this.label1_Click);
            // 
            // label2
            // 
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(12, 80);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(137, 12);
            this.label2.TabIndex = 3;
            this.label2.Text = "UseSystemPassWordChar:";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(318, 151);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.textBox2);
            this.Controls.Add(this.textBox1);
            this.Name = "Form1";
            this.Text = "登錄";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
    }
}