Simple calculator in WinForms

//Form1.cs
  private void AddButton_Click(object sender, EventArgs e) {
            if (FirstNumber.Text == "" && SecondNumber.Text == "") {
                Answer.Text = "";
                return;
            }
            this.Answer.Text = ((Int32.Parse(FirstNumber.Text)) + (Int32.Parse(SecondNumber.Text))).ToString();
        }

// Form1.Designer.cs
namespace WindowsFormsApplication1 {
    partial class Form1 {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing) {
            if (disposing && (components != null)) {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent() {
            this.AddButton = new System.Windows.Forms.Button();
            this.FirstNumber = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.SecondNumber = new System.Windows.Forms.TextBox();
            this.label3 = new System.Windows.Forms.Label();
            this.label4 = new System.Windows.Forms.Label();
            this.Answer = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            //
            // AddButton
            //
            this.AddButton.Location = new System.Drawing.Point(128, 76);
            this.AddButton.Name = "AddButton";
            this.AddButton.Size = new System.Drawing.Size(100, 29);
            this.AddButton.TabIndex = 0;
            this.AddButton.Text = "Add";
            this.AddButton.UseVisualStyleBackColor = true;
            this.AddButton.Click += new System.EventHandler(this.AddButton_Click);
            //
            // FirstNumber
            //
            this.FirstNumber.AccessibleRole = System.Windows.Forms.AccessibleRole.Text;
            this.FirstNumber.Location = new System.Drawing.Point(128, 22);
            this.FirstNumber.Name = "FirstNumber";
            this.FirstNumber.Size = new System.Drawing.Size(100, 20);
            this.FirstNumber.TabIndex = 1;
            this.FirstNumber.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            //
            // label1
            //
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(41, 25);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(69, 13);
            this.label1.TabIndex = 2;
            this.label1.Text = "First Number:";
            //
            // SecondNumber
            //
            this.SecondNumber.Location = new System.Drawing.Point(128, 48);
            this.SecondNumber.Name = "SecondNumber";
            this.SecondNumber.Size = new System.Drawing.Size(100, 20);
            this.SecondNumber.TabIndex = 8;
            this.SecondNumber.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            //
            // label3
            //
            this.label3.AutoSize = true;
            this.label3.Location = new System.Drawing.Point(41, 51);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(87, 13);
            this.label3.TabIndex = 9;
            this.label3.Text = "Second Number:";
            this.label3.Click += new System.EventHandler(this.label3_Click);
            //
            // label4
            //
            this.label4.AutoSize = true;
            this.label4.Location = new System.Drawing.Point(41, 111);
            this.label4.Name = "label4";
            this.label4.Size = new System.Drawing.Size(45, 13);
            this.label4.TabIndex = 10;
            this.label4.Text = "Answer:";
            //
            // Answer
            //
            this.Answer.AccessibleRole = System.Windows.Forms.AccessibleRole.Text;
            this.Answer.Location = new System.Drawing.Point(128, 111);
            this.Answer.Name = "Answer";
            this.Answer.ReadOnly = true;
            this.Answer.Size = new System.Drawing.Size(100, 20);
            this.Answer.TabIndex = 11;
            this.Answer.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
            //
            // Form1
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(269, 146);
            this.Controls.Add(this.Answer);
            this.Controls.Add(this.label4);
            this.Controls.Add(this.label3);
            this.Controls.Add(this.SecondNumber);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.FirstNumber);
            this.Controls.Add(this.AddButton);
            this.Name = "Form1";
            this.Text = "Simple Calculator";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button AddButton;
        private System.Windows.Forms.TextBox FirstNumber;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.TextBox SecondNumber;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.Label label4;
        private System.Windows.Forms.TextBox Answer;
    }
}