在另一个函数中调用返回布尔值的函数

本文关键字：函数 布尔值 返回 另一个 调用 | 更新日期: 2023-09-27 18:06:29

我需要在另一个函数中调用下面的函数。我不知道怎么做?

private int IsValidUser()
{            
    int result = 0;
    string strQuery = "Select Email From AUser Where Email = @Email And Password = @Password ";
    SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.AppSettings["ConnectionString"]);
    SqlCommand Cmd = new SqlCommand(strQuery, con);
    //Cmd.CommandType = CommandType.StoredProcedure;
    Cmd.Parameters.AddWithValue("@Email", txtEmail.Text);
    Cmd.Parameters.AddWithValue("@Password", txtPassword.Text);
    con.Open();
    result = (int)Cmd.ExecuteScalar();
    if (result > 0)
    {
        //Session["SessionEmail"] = txtEmail.Text;
        Session[General.S_USEREMAIL] = txtEmail.Text;
        Response.Redirect("~/frmMyAccountMyProfile.aspx");
    }
    else
    {
        Literal1.Text = "Invalid Email/Password!";
    }
}

我试图调用它如下按钮点击事件。

protected void btnSignIn_Click(object sender, EventArgs e)
{
    // Authenticate User
    bool blnValidUser = false;
    IsValidUser();
    blnValidUser = Convert.ToBoolean(IsValidUser().result.Value);
    if (blnValidUser)
    {
        // on Success - If remember me > Save to cookies
        //SaveUserDetailsToCookie();                       
    }
    else
    {
        // on Failure - Show error msg
    }
}

在另一个函数中调用返回布尔值的函数

你的函数IsValidUser被设计为返回一个int

(不管出于什么原因，我不知道，因为它不返回任何东西。这段代码永远不会编译。)

你可以修复它，通过让它像这样返回一个bool:

private bool IsValidUser()
{
        int result = 0;
        //since executeScalar is intended to retreive only a single value
        //from a query, we select the number of results instead of the email address
        //of each matching result.
        string strQuery = "Select COUNT(Email) From AUser Where Email = @Email And Password = @Password ";
        SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.AppSettings["ConnectionString"]);
        SqlCommand Cmd = new SqlCommand(strQuery, con);
        //Cmd.CommandType = CommandType.StoredProcedure;
        Cmd.Parameters.AddWithValue("@Email", txtEmail.Text);
        Cmd.Parameters.AddWithValue("@Password", txtPassword.Text);
        con.Open();
        result = (int)Cmd.ExecuteScalar();
        //returning a boolean comparator works like this :
        //will return true if the result is greater than zero, but false if it is not.
        return result > 0;
}

然后你可以像这样调用你的函数:

blnValidUser = IsValidUser();

IsValidUser返回一个显然没有result属性的int。但我假设你只是想使用这个值:

int valUserResult = IsValidUser();
bool blnValidUser = valUserResult == 1;

但是你应该考虑首先返回一个bool，因为这样会更容易读:

private bool IsValidUser()
{            
    bool result = false;
    // ...
    return result;
}

将函数修改如下 

private int IsValidUser()
   {
    int result = 0;
    string strQuery = "Select Email From AUser Where Email = @Email And Password = @Password ";
    SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.AppSettings["ConnectionString"]);
    SqlCommand Cmd = new SqlCommand(strQuery, con);
    //Cmd.CommandType = CommandType.StoredProcedure;
    Cmd.Parameters.AddWithValue("@Email", txtEmail.Text);
    Cmd.Parameters.AddWithValue("@Password", txtPassword.Text);
    con.Open();
    result = (int)Cmd.ExecuteScalar();
    if (result > 0)
    {
        //Session["SessionEmail"] = txtEmail.Text;
        Session[General.S_USEREMAIL] = txtEmail.Text;
        Response.Redirect("~/frmMyAccountMyProfile.aspx");
    }
    else
    {
        Literal1.Text = "Invalid Email/Password!";
    }
     return result;
}
}

并按如下方式调用

protected void btnSignIn_Click(object sender, EventArgs e)
 {
    // Authenticate User
    int blnValidUser = IsValidUser();
    //Check if blnValidUser is greater than 0.
    //IsValidUser() will return value greater than 0 if the sql is successful else will return 0
    if (blnValidUser > 0)
    {
        // on Success - If remember me > Save to cookies
        //SaveUserDetailsToCookie();                       
    }
    else
    {
        // on Failure - Show error msg
    }
}
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