C# 非静态字段、方法或属性需要对象引用'；WindowsFormsApplication1.Form1.label1'；

我想重用一段代码，所以我想我会用一个包含该代码的方法创建一个类，然后在需要的地方调用该方法

我举了一个简单的例子来说明我的问题：

Form1.cs

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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void Form1_Load(object sender, EventArgs e)
        {
            LoadText.getText();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        public static void getText()
        {
            WindowsFormsApplication1.Form1.label1.Text = "New label1 text";
        }
    }
}

LoadText.cs

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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void Form1_Load(object sender, EventArgs e)
        {
            LoadText.getText();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        public static void getText()
        {
            WindowsFormsApplication1.Form1.label1.Text = "New label1 text";
        }
    }
}

正如您所看到的，我有一个带有标签的表单，我想使用我的另一个方法（LoadText中的getText）来更改标签的文本

以下是我的错误消息：

非静态字段、方法或属性“WindowsFormsApplication1.Form1.label1”需要对象引用**

我已经在设计中将label1从私人更改为公共

---

如何解决此问题？

您需要对表单的引用才能访问其元素。

问题在于

Form1

是一个类，而不是一个对象

label1

不是类的静态成员，它是

Form1

实例的成员。因此出现了错误，它告诉您需要一个对象实例（属于

Form1

类）

请尝试以下操作：

Form1.cs:

LoadText.getText(label1);

public static void getText(Label lbl)
{
    lbl.Text = "New label1 text";
}

 // here a static method is created to assign text to the public Label
 public static void textReplaceWith(String s, Label label)
 {
     label.Text = s;
 }

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        //new label declared as a static var
        public static Label pLabel;

        //this method runs when your form opens
        public LoadTextForm() 
        {
            pLabel = Label1; //assign your private label to the static one
        }

        //Any time getText() is used, the label text updates no matter where it's used
        public static void getText()
        {
           Form1.textReplaceWith("New label1 text", pLabel); //Form1 method's used 
        }
    }
}

LoadText.cs:

LoadText.getText(label1);

public static void getText(Label lbl)
{
    lbl.Text = "New label1 text";
}

 // here a static method is created to assign text to the public Label
 public static void textReplaceWith(String s, Label label)
 {
     label.Text = s;
 }

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        //new label declared as a static var
        public static Label pLabel;

        //this method runs when your form opens
        public LoadTextForm() 
        {
            pLabel = Label1; //assign your private label to the static one
        }

        //Any time getText() is used, the label text updates no matter where it's used
        public static void getText()
        {
           Form1.textReplaceWith("New label1 text", pLabel); //Form1 method's used 
        }
    }
}

现在有了一个静态方法，它将接受一个

标签
对象，并将其文本设置为“newlabel1 text”

有关
静态
修改器的更多信息，请参见以下链接：


这是OO编程新手的一个常见问题

如果要使用对象的方法，则需要创建对象的实例（使用new）。除非，否则该方法不需要对象本身，在这种情况下，可以（而且应该）将其声明为静态。
我尝试了另一种方法，该方法同样有效：

Form1.cs:

LoadText.getText(label1);

public static void getText(Label lbl)
{
    lbl.Text = "New label1 text";
}

 // here a static method is created to assign text to the public Label
 public static void textReplaceWith(String s, Label label)
 {
     label.Text = s;
 }

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        //new label declared as a static var
        public static Label pLabel;

        //this method runs when your form opens
        public LoadTextForm() 
        {
            pLabel = Label1; //assign your private label to the static one
        }

        //Any time getText() is used, the label text updates no matter where it's used
        public static void getText()
        {
           Form1.textReplaceWith("New label1 text", pLabel); //Form1 method's used 
        }
    }
}

LoadText.cs:

LoadText.getText(label1);

public static void getText(Label lbl)
{
    lbl.Text = "New label1 text";
}

 // here a static method is created to assign text to the public Label
 public static void textReplaceWith(String s, Label label)
 {
     label.Text = s;
 }

namespace WindowsFormsApplication1
{
    public class LoadText : Form1
    {
        //new label declared as a static var
        public static Label pLabel;

        //this method runs when your form opens
        public LoadTextForm() 
        {
            pLabel = Label1; //assign your private label to the static one
        }

        //Any time getText() is used, the label text updates no matter where it's used
        public static void getText()
        {
           Form1.textReplaceWith("New label1 text", pLabel); //Form1 method's used 
        }
    }
}

这将允许您使用公共方法从任意位置更改标签的文本变量。希望这有帮助：）