Error when trying to get an int from textbox

Question

I am new to C# and programming in general. I was able to create the required program in Console but want to get one working with Forms as well. I am running into an issue wh

Answer 1

I updated your code, you were using variables with the same names as your actual text boxes... That's not a good idea:

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

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

            private void button1_Click(object sender, EventArgs e)
            {
                int length;
                int width;
                int height;
                int paint;
                int answer;

                    length = int.Parse(LengthtextBox.Text);
                    width = int.Parse(WidthtextBox.Text);
                    height = int.Parse(HeighttextBox.Text);
                    paint = 350;

                    answer = (length* width* height) / paint;

                    MessageBox.Show( answer.ToString() );

            }

        }
    }

    namespace Paint_Determinator_Form
    {
        partial class Form1
        {
            /// 

            /// Required designer variable.
            /// 
            private System.ComponentModel.IContainer components = null;

            /// 

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

            #region Windows Form Designer generated code

            /// 

            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// 
            private void InitializeComponent()
            {
                this.label1 = new System.Windows.Forms.Label();
                this.label2 = new System.Windows.Forms.Label();
                this.label3 = new System.Windows.Forms.Label();
                this.label4 = new System.Windows.Forms.Label();
                this.WidthtextBox = new System.Windows.Forms.TextBox();
                this.HeighttextBox = new System.Windows.Forms.TextBox();
                this.LengthtextBox = new System.Windows.Forms.TextBox();
                this.button1 = new System.Windows.Forms.Button();
                this.SuspendLayout();
                // 
                // label1
                // 
                this.label1.AutoSize = true;
                this.label1.Location = new System.Drawing.Point(28, 29);
                this.label1.Name = "label1";
                this.label1.Size = new System.Drawing.Size(454, 13);
                this.label1.TabIndex = 0;
                this.label1.Text = "Welcome to Paint Determinator! Please enter the measurements in the appropriate f" +
        "ields below!";
                // 
                // label2
                // 
                this.label2.AutoSize = true;
                this.label2.Location = new System.Drawing.Point(28, 91);
                this.label2.Name = "label2";
                this.label2.Size = new System.Drawing.Size(35, 13);
                this.label2.TabIndex = 1;
                this.label2.Text = "Width";
                // 
                // label3
                // 
                this.label3.AutoSize = true;
                this.label3.Location = new System.Drawing.Point(28, 139);
                this.label3.Name = "label3";
                this.label3.Size = new System.Drawing.Size(38, 13);
                this.label3.TabIndex = 2;
                this.label3.Text = "Height";
                // 
                // label4
                // 
                this.label4.AutoSize = true;
                this.label4.Location = new System.Drawing.Point(28, 183);
                this.label4.Name = "label4";
                this.label4.Size = new System.Drawing.Size(40, 13);
                this.label4.TabIndex = 3;
                this.label4.Text = "Length";
                // 
                // WidthtextBox
                // 
                this.WidthtextBox.Location = new System.Drawing.Point(175, 83);
                this.WidthtextBox.Name = "WidthtextBox";
                this.WidthtextBox.Size = new System.Drawing.Size(100, 20);
                this.WidthtextBox.TabIndex = 5;
                // 
                // HeighttextBox
                // 
                this.HeighttextBox.Location = new System.Drawing.Point(175, 131);
                this.HeighttextBox.Name = "HeighttextBox";
                this.HeighttextBox.Size = new System.Drawing.Size(100, 20);
                this.HeighttextBox.TabIndex = 6;
                // 
                // LengthtextBox
                // 
                this.LengthtextBox.Location = new System.Drawing.Point(175, 183);
                this.LengthtextBox.Name = "LengthtextBox";
                this.LengthtextBox.Size = new System.Drawing.Size(100, 20);
                this.LengthtextBox.TabIndex = 7;
                // 
                // button1
                // 
                this.button1.Location = new System.Drawing.Point(349, 402);
                this.button1.Name = "button1";
                this.button1.Size = new System.Drawing.Size(75, 23);
                this.button1.TabIndex = 9;
                this.button1.Text = "Paint";
                this.button1.UseVisualStyleBackColor = true;
                // 
                // Form1
                // 
                this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
                this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
                this.ClientSize = new System.Drawing.Size(511, 447);
                this.Controls.Add(this.button1);
                this.Controls.Add(this.LengthtextBox);
                this.Controls.Add(this.HeighttextBox);
                this.Controls.Add(this.WidthtextBox);
                this.Controls.Add(this.label4);
                this.Controls.Add(this.label3);
                this.Controls.Add(this.label2);
                this.Controls.Add(this.label1);
                this.Name = "Form1";
                this.Text = "Form1";
                this.ResumeLayout(false);
                this.PerformLayout();

            }

            #endregion

            private System.Windows.Forms.Label label1;
            private System.Windows.Forms.Label label2;
            private System.Windows.Forms.Label label3;
            private System.Windows.Forms.Label label4;
            private System.Windows.Forms.TextBox WidthtextBox;
            private System.Windows.Forms.TextBox HeighttextBox;
            private System.Windows.Forms.TextBox LengthtextBox;
            private System.Windows.Forms.Button button1;
        }