Question

我从C＃Windows应用程序中收到以下错误：

错误1'CreateLabelInPanel'没有重载匹配委托'WorksOrderStore.ProcessDbConnDetailsDelegate'H：\ c \ WorksOrderFactory \ WorksOrderFactory \ WorksOrderClient.cs 43 39 WorksOrderFactory

我有3个.cs文件，基本上是：

打开一个窗口
有用户连接数据库的选项
选择该选项后，系统将关闭并连接到数据库，并加载一些数据（暂时只测试数据）
然后使用委托，系统应该做soemthing，测试将创建一个标签。但是我还没有对这部分进行编码。

但是在我将此错误排序之前，我无法构建。

这三个人被称为：

WorksOrderClient.cs（主要是）
WorksOrderStore.cs
LoginBox.cs

以下是每个文件的代码：

WorksOrderClient.cs：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using WorksOrderStore;
namespace WorksOrderFactory
{
    using WorksOrderStore;

    public partial class WorksOrderClient : Form
    {   
        LoginBox lb = new LoginBox();
        private static WorksOrderDB wodb = new WorksOrderDB();

        private static int num_conns = 0;

        public WorksOrderClient()
        {
            InitializeComponent();
        }

        private void connectToADBToolStripMenuItem_Click(object sender, EventArgs e)
        {
            lb.ShowDialog();
            lb.Visible = true;
        }

        public static bool createDBConnDetObj(string username, string password, string database)
        {
            // increase the number of connections
            num_conns = num_conns + 1;
            // create the connection object
            wodb.AddDbConnDetails(username, password, database, num_conns);
            // create a new delegate object associated with the static
            // method WorksOrderClient.createLabelInPanel
            wodb.ProcessDbConnDetails(new ProcessDbConnDetailsDelegate(CreateLabelInPanel));
            return true;
        }

        static void CreateLabelInPanel(DbConnDetails dbcd)
        {
            Console.Write("hellO");
            string tmp = (string)dbcd.username;
            //Console.Write(tmp);
        }

        private void WorksOrderClient_Load(object sender, EventArgs e)
        {

        }

    }
}

WorksOrderStore.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using WorksOrderFactory;

namespace WorksOrderStore
{
    using System.Collections;

    // Describes a book in the book list:
    public struct WorksOrder
    {
        public string contractor_code { get; set; } // contractor ID
        public string email_address { get; set; }   // contractors email address
        public string date_issued { get; set; }     // date the works order was issued
        public string wo_ref { get; set; }          // works order ref
        public string status { get; set; }          // status ... not used
        public job_status js { get; set; }          // status of this worksorder within this system

        public WorksOrder(string contractor_code, string email_address, string date_issued, string wo_ref) : this()
        {
            this.contractor_code = contractor_code;
            this.email_address = email_address;
            this.date_issued = date_issued;
            this.wo_ref = wo_ref;
            this.js = job_status.Pending;
        }
    }

    // Declare a delegate type for processing a WorksOrder:
    //public delegate void ProcessWorksOrderDelegate(WorksOrder worksorder);

    // Maintains a worksorder database.
    public class WorksOrderDB
    {
        // List of all worksorders in the database:
        ArrayList list = new ArrayList();

        // Add a worksorder to the database:
        public void AddWorksOrder(string contractor_code, string email_address, string date_issued, string wo_ref)
        {
            list.Add(new WorksOrder(contractor_code, email_address, date_issued, wo_ref));
        }


        // Call a passed-in delegate on each pending works order to process it: 
        /*public void ProcessPendingWorksOrders(ProcessWorksOrderDelegate processWorksOrder)
        {
            foreach (WorksOrder wo in list)
            {
                if (wo.js.Equals(job_status.Pending))
                    // Calling the delegate:
                    processWorksOrder(wo);
            }
        }*/

        // Add a DbConnDetails to the database:
        public void AddDbConnDetails(string username, string password, string database, int conn_num)
        {
            list.Add(new DbConnDetails(username, password, database, conn_num));
        }

        // Call a passed-in delegate on each dbconndet to process it: 
        public void ProcessDbConnDetails(ProcessDbConnDetailsDelegate processDBConnDetails)
        {
            foreach (DbConnDetails wo in list)
            {
                processDBConnDetails(wo);
            }
        }
    }

    // statuses for worksorders in this system
    public enum job_status
    {
        Pending,
        InProgress,
        Completed
    }


    public struct DbConnDetails
    {
        public string username { get; set; } // username
        public string password { get; set; } // password
        public string database { get; set; } // database
        public int conn_num { get; set; } // this objects connection number.
        public ArrayList woList { get; set; }  // list of works orders for this connection

        // this constructor just sets the db connection details
        // the woList array will get created later .. not a lot later but a bit.
        public DbConnDetails(string username, string password, string database, int conn_num) : this()
        {
            this.username = username;
            this.password = password;
            this.database = database;
            this.conn_num = conn_num;
            woList = new ArrayList();
        }
    }

    // Declare a delegate type for processing a DbConnDetails:
    public delegate void ProcessDbConnDetailsDelegate(DbConnDetails dbConnDetails);
}

LoginBox.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WorksOrderFactory
{
    public partial class LoginBox : Form
    {
        public LoginBox()
        {
            InitializeComponent();
        }

        private void LoginBox_Load(object sender, EventArgs e)
        {
            this.Visible = true;
            this.Show();
            //usernameText.Text = "Username";
            //new Font(usernameText.Font, FontStyle.Italic);
        }

        private void cancelBtn_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void loginBtn_Click(object sender, EventArgs e)
        {
            // set up a connection details object.
            bool success = WorksOrderClient.createDBConnDetObj(usernameText.Text, passwordText.Text, databaseText.Text);

        }

        private void LoginBox_Load_1(object sender, EventArgs e)
        {

        }


    }
}

任何想法??

干杯，

米

Answer 1

在将委托的定义与您尝试使用的方法的定义进行比较时，有一件事情会跳出来：

static void CreateLabelInPanel(DbConnDetails dbcd)
public delegate void ProcessDbConnDetailsDelegate(DbConnDetails dbConnDetails)

CreateLabelInPanel可能不应该声明为静态。

Answer 2

编译器只是说你提供给委托的方法与委托所期望的签名不匹配。

所以，在你的情况下。

//To get this line working...
 wodb.ProcessDbConnDetails(new ProcessDbConnDetailsDelegate(SomeMethod1));

//The method signature should be like this.
static void SomeMethod1(DbConnDetails dbcd)

//OR even this -- Instance/Static methods can be supplied to same delegate.
void SomeInstanceMethod(DbConnDetails dbcd)..

如果没有，编译器会抱怨。

另外，你有两个名为“DbConnDetails”的课程吗？我最好的猜测是你指的是“DbConnDetails”，它位于与委托人所期望的名称空间不同的名称空间中。

Answer 3

感谢@amby和@massif以及我可能错过的其他任何人。

这是学校男生的错误。

事实证明我有另一个文件（我认为我已删除），它还包含一个名为DbConnDetails的类和构造函数。我在解决方案中搜索了DbConnDetails。

为了安全起见，我还重命名了类/构造函数和文件名。

然后我宣布

static void CreateLabelInPanel(DbConnDetails dbcd)

这意味着应用程序现在再次编译/构建。

再次感谢大家。

C＃委托问题

3 个答案: