尝试从文本框中获取 int 时出错答案

【问题标题】：Error when trying to get an int from textbox尝试从文本框中获取 int 时出错
【发布时间】：2014-02-03 06:06:39
【问题描述】：

我是 C# 和一般编程的新手。我能够在 Console 中创建所需的程序，但也希望获得一个使用 Forms 的程序。尝试从文本框中获取 int 时遇到问题。

在调试时出现错误：

错误 3 'int' 不包含 'Text' 的定义，并且找不到接受第一个类型为 'int' 的参数的扩展方法 'Text'（您是否缺少 using 指令或程序集引用？） D :\Dropbox\Classwork\C_Sharp\InProgress\PaintDeterminator\Paint Determinator Form\Paint Determinator Form\Form1.cs 30 57 Paint Determinator Form

这是我目前编写的代码。

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 LengthtextBox;
            int WidthtextBox;
            int HeighttextBox;
            int paint;
            int answer;

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

                answer = (LengthtextBox * WidthtextBox * HeighttextBox) / paint;

                MessageBox.Show( answer.ToString() );

        }

    }
}

namespace Paint_Determinator_Form
{
    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.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;
    }

【问题讨论】：

我强烈建议不要定义与类级成员同名的局部变量。抛开范围问题不谈，它让代码非常难以理解。
只是一个建议 - 不要将您的内部变量命名为与文本框控件相同的名称，这非常令人困惑。
我已经编辑了你的标题。请参阅“Should questions include “tags” in their titles?”，其中的共识是“不，他们不应该”。
谢谢大家。约翰我不知道，将来会修改。感谢大家启发我并继续前进，我不会用同样的名字命名。非常感谢。

标签： c# winforms

【解决方案1】：

您正在声明将替换您的实际文本框的本地范围变量。您应该使用具有不同名称的局部变量，例如：

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

【讨论】：

【解决方案2】：

在你的情况下最好重命名整数，但你也可以在类似的情况下使用它

LengthtextBox = int.Parse(this.LengthtextBox.Text);
WidthtextBox = int.Parse(this.WidthtextBox.Text);
HeighttextBox = int.Parse(this.HeighttextBox.Text);

我认为，如果您是编程新手，最好了解这一点，而不是在不理解的情况下重命名变量。

【讨论】：

【解决方案3】：

从button1_Click() 方法中删除这些定义，因为您在此方法中使用与类变量相同的名称：

int LengthtextBox;
int WidthtextBox;
int HeighttextBox;

并更改变量的名称：

int length;
int width;
int height;

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

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

【讨论】：

【解决方案4】：

为什么你把你的整数命名为你的文本框？这确实是一种糟糕的做法，并且在最根本的层面上令人困惑。如您所见，编译器认为您使用的是 int 变量而不是文本框，并抱怨 int 类型没有名为 Text 的属性。

所以只需在点击方法中更改整数的名称

   private void button1_Click(object sender, EventArgs e)
   {
        int l;
        int w;
        int h;
        int paint;
        int answer;

        l = int.Parse(LengthtextBox.Text);
        w = int.Parse(WidthtextBox.Text);
        h = int.Parse(HeighttextBox.Text);
        paint = 350;

        answer = (l * w * h) / paint;

         MessageBox.Show( answer.ToString() );
    }

也就是说，我建议使用Int32.TryParse 将用户输入的数据转换为有效整数。如果您的用户键入的内容无法转换为整数，Parse 方法将引发异常，而不是 TryParse 返回 false 而不会产生代价高昂的异常

例如

  int l;
  if(!Int32.TryParse(LengthtextBox.Text, out l))
  {
       MessageBox.Show("Please type a valid number for Length");
       return;
  }

当 Int32.TryParse 返回时，输出参数 (l) 包含 32 位有符号整数值，相当于您的数字中包含的数字文本框，如果转换成功，或者如果转换失败则为零

【讨论】：

史蒂夫，谢谢！仍然低于 15 名声望，所以我不能投票给你，但你以一种我很容易理解的方式解释了它。这是针对在线课程的，虽然书籍和在线材料很有帮助，但当您有问题时，很难对某个问题进行推断。

【解决方案5】：

我更新了您的代码，您使用的变量名称与您的实际文本框名称相同...这不是一个好主意：

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
        {
            /// <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.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;
        }

【讨论】：

您的新变量名称有点误导。我会直观地期望像 textBoxLength 和 textBoxWidth 这样的东西来描述 TextBox 的尺寸。
赞成，因为你是对的。我用新名称更新了代码... :)
作为任何类型编程的菜鸟，谢谢。出于某种原因，我认为实体的名称必须与文本框的名称相同。