名称"MessageBox"在当前上下文中不存在 [英] The name 'MessageBox' does not exist in the current context

问题描述

public class Class1
   {


       public static void OpenConnection()
       {
           SqlConnection cn;
           cn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename='D:\My_Project\My_Project\DATABASE\Soneri_Bank_loan_system.mdf';Integrated Security=True;Connect Timeout=30;User Instance=True");
               try
               {
                   cn.Open();
               }
               catch (Exception e1)
               {

                   MessageBox.Show(e1.Message);
               }
           }

推荐答案

如果您在类文件中使用MessageBox，则必须导入

if u r using MessageBox in class file then u have to import

System.Windows.Forms

命名空间才能使用消息框

namespace to use message box

您的班级文件

your class File

public class Class1
   {


       public static void OpenConnection()
       {
           SqlConnection cn;
           cn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename='D:\My_Project\My_Project\DATABASE\Soneri_Bank_loan_system.mdf';Integrated Security=True;Connect Timeout=30;User Instance=True");
               try
               {
                   cn.Open();
               }
               catch (Exception e1)
               {

                   MessageBox.Show(e1.Message);
               }
           }

这是您的表单类

this is your Form Class

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, System.EventArgs e)
    {
        Class1.OpenConnection();//this is your Static function that u have created in Class 1//
    }

   
    }
}

public class Class1
   {

public static SqlConnection cn;
	cn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename='D:\My_Project\My_Project\DATABASE\Soneri_Bank_loan_system.mdf';Integrated Security=True;Connect Timeout=30;User Instance=True");

       public static void OpenConnection()
       {
           
               try
               {
                   cn.Open();
               }
               catch (Exception e1)
               {

                   MessageBox.Show(e1.Message);
               }
           }
}

并在form.cs和class1.cs文件中导入System.Data.SqlClient，然后尝试

and import System.Data.SqlClient in form.cs and class1.cs file and try

这篇关于名称"MessageBox"在当前上下文中不存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！