C# 只有赋值、调用、递增、递减、等待和新对象表达式可以用作错误C语句#

当我试图创建一个float并在创建它之后设置它的值时，我遇到了一个错误，我得到了这个错误。我对正在发生的事情感到非常困惑，因为它与上面的代码相同，除了它是一个浮点。这是我的密码

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

        string DOW;
        private void ComboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            DOW = comboBox1.Text;
        }

        int carrotSales;
        float carrotEarnings;
        private void Add1_Click(object sender, EventArgs e)
        {
            carrotSales++;
            carrotEarnings + 1.50; //error is here
            writeTotal1();
            writeEarnings1();
        }

        void writeTotal1()
        {
            total1.Text = "Total: " + carrotSales;
        }

        void writeEarnings1()
        {
            earnings1.Text = "Earnings: $" + carrotEarnings;
        }

        int gAppleSales;
        private void Add2_Click(object sender, EventArgs e)
        {
            gAppleSales++;
            writeTotal2();
        }

        void writeTotal2()
        {
            total2.Text = "Total: " + gAppleSales;
        }
    }
}

我已经尝试在那里添加一个

1.50f

，但它没有修复它

---

任何帮助都很好。非常感谢。

替换您的函数Add1\u单击如下所示

private void Add1_Click(object sender, EventArgs e)
{
     carrotSales++;
     carrotEarnings = carrotEarnings + 1.50; //error is here
     writeTotal1();
     writeEarnings1();
 }

---

您已经初始化了浮点变量

浮动收益

在不初始化变量值的情况下，您正在尝试增加变量。初始化变量，如下所示

浮动收益=0.0f

---

do

carrogenders=carrogenders+1.50f

或

胡萝卜收益+=1.50f

。您是否更改胡萝卜收益+1.50；要获得收益+=1.50f；？