Question

asp.net中运算符“==”无法应用于“方法组”和“string”类型的操作数

protected void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text.Trim() == "" || TextBox2.Text.Trim == "")
{
if (TextBox1.Text.Trim() == "" && TextBox2.Text.Trim() == "")
Response.Write("<script>alert(\"用户名和密码不能为空！\");</script>");
else if (TextBox1.Text.Trim() == "")
Response.Write("<script>alert(\"用户名不能为空！\");</script>");
else if (TextBox2.Text.Trim() == "")
Response.Write("<script>alert(\"密码不能为空！\");</script>");
}
else
{
int count = 0;
if (DropDownList1.SelectedValue == "学生")
{
int exist;
exist=(new projclass()).ifstuexist(TextBox1.Text);
if (exist == 1)
{
count = (new projclass()).getstu(TextBox1.Text,TextBox2.Text);
if (count == 1)
{
string 学号 = TextBox1.Text.ToString();
Session["学号"] = 学号;
Response.Redirect("student.aspx");
}
else Response.Write("<script>alert(\"密码错误!请重新输入\");</script>");
}
else Response.Write("<script>alert(\"学号不存在！请确认学号输入正确\");</script>");
}

Answer 1

这句代码 if (TextBox1.Text.Trim() == "" || TextBox2.Text.Trim == "")
改为if (TextBox1.Text.Trim() == "" || TextBox2.Text.Trim() == "")

后面的trim方法少了个括号

Answer 2

trim() 是方法，清除字符串前后的空格