帮忙看看哪里错了

Question

  if (button1.Text == "保存"&&textBox1 .Text !="")
                {
                    try
                    {
                        con.Open();\\前面已声明静态字段CON
                        string insertcmd = "insert into TbRenyuan(User_Name,User_Phone,User_Email,Dept_Kename) values('" + textBox1.Text + "','" + textBox2.Text + "','" + textBox3.Text + "','" + textBox4.Text + "')";                                                OleDbCommand cmd = new OleDbCommand(insertcmd, con);
                         
                        int i = cmd.ExecuteNonQuery();
                        if (i>0)
                        {
                            MessageBox.Show("保存成功");
                        }
                        button1.Text = "添加";
                        this.textBox1.Enabled = false;
                        this.textBox2.Enabled = false;
                        this.textBox3.Enabled = false;
                        this.textBox4.Enabled = false;
                        con.Close();
                        con.Dispose();
                        cmd.Dispose();
                    }
                    catch(Exception ex) { MessageBox.Show("错误:尚未保存成功"+ex.Message);}
                 
                }错误是connection属性尚未初始化！
高手帮忙解决下，小弟新手！

Answer 1

 con分配内存没有？
没有的话要先 new OleDbConnection();
而且要指定连接字

Answer 2

con.Open();\\前面已声明静态字段CON 
声名的时候有没有new?

Answer 3

con= new OleDbConnection(“连接字”); 
这样也可以

Answer 4

连接数据要从Connection开始.你的connection属性尚未初始化就是OleDbConnection没有初始化.给你一个access连接例子
      OleDbConnection myconn=new OleDbConnection();
     myconn.ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0; Data Source=mydb.mdb;";
     myconn.Open();
     string strsql="select * from mytable";
     OleDbCommand mycmd=new OleDbCommand(strsql,myconn);