Question

C# 运算符“*”无法应用于“double”和“string”类型的操作数

double x = double.Parse(textBox1.Text);
double y = double.Parse(textBox2.Text);
double z = double.Parse(textBox3.Text);
label8.Text = 1.2*(x)+1.4*(y).ToString();
label9.Text = 1.35*(x)+1.4*0.7*(y).ToString();
label10.Text = 1.2*((x)+0.5*(y))+1.3*(z).ToString();
label11.Text = 1.2*((x)+0.5*(y))-1.3*(z).ToString();

Answer 1

label8.Text = (1.2*(x)+1.4*(y)).ToString();
要把tostring前面括起来
否则就是把最近一个tostring了，自然就没办法和double运算了