WinForms：WindowsFormsApplication常用的核心基础

1.登陆模块

    private void btnLogin_Click(object sender, EventArgs e)
        {
            if (txtUserID .Text .Trim()==""|| txtPassword .Text .Trim ()=="" || cmbStatus .Text .Trim ()=="")
            {
                MessageBox.Show("输入错误，请重新输入！", "提示");
                return;
            }
            if (cmbStatus.Text .Equals("管理员"))
            {
                SqlConnection conn = PubClass.getconnection();
                conn.Open();
                string strSql = "select * from Teachers where ID='" + txtUserID.Text.Trim() + "' and PWD='" + txtPassword.Text.Trim() + "'";
                DataSet ds = new DataSet();
                try
                {

                    SqlDataAdapter da = new SqlDataAdapter(strSql, conn);
                    da.Fill(ds, "Teachers");
                    if (ds.Tables["Teachers"].Rows.Count > 0)
                    {
                        PubClass.loginID = txtUserID.Text;
                        PubClass.loginStatus = "管理员";
                        frmMain main = new frmMain();
                        this.Hide();
                        main.Show();
                    }
                    else
                    {
                        MessageBox.Show("用户名、密码或身份错误，请重新输入！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        txtUserID.Text = "";
                        txtPassword.Text = "";
                        cmbStatus.Text = "管理员";
                        txtUserID.Focus();
                    }
                }
                finally
                {
                    conn.Close();
                }
            }
           }

2.连接数据库模块

public static SqlConnection getconnection()

 {  
            string strConn = @"Data Source=PING-PC;Initial Catalog=C:\……\STUDENTSINFODATABASE.MDF;Persist Security Info=True;User ID=sa;password=123";
            return new SqlConnection(strConn);
}

3.添加数据模块

        public static void insert(string strSql)
        {
            SqlConnection conn = getconnection();
            conn.Open();
            try
            {
                SqlCommand cmd = new SqlCommand(strSql, conn);
                if (cmd.ExecuteNonQuery() > 0)
                {
                    MessageBox.Show("添加成功!", "提示");
                }
                else
                {
                    MessageBox.Show("添加失败！", "提示");
                }
            }
            catch
            {
                MessageBox.Show("添加失败，请确认添加的信息是否重复！", "提示");
            }
            finally 
            {
                conn.Close();
            }
         }

4.删除数据模块

public static void delete(string strSql)
        {
            SqlConnection conn = getconnection();
            conn.Open();
            try
            {
                SqlCommand cmd = new SqlCommand(strSql, conn);
                if (cmd.ExecuteNonQuery() > 0)
                {
                    MessageBox.Show("删除成功!", "提示");
                }
                else
                {
                    MessageBox.Show("删除失败！", "提示");
                }
            }
            catch
            {
                MessageBox.Show("删除失败！", "提示");
            }
            finally  
            {
                conn.Close();
                
            }
        }

5.修改数据模块

public static void insert(string strSql)
        {
            SqlConnection conn = getconnection();
            conn.Open();
            try
            {
                SqlCommand cmd = new SqlCommand(strSql, conn);
                if (cmd.ExecuteNonQuery() > 0)
                {
                    MessageBox.Show("添加成功!", "提示");
                }
                else
                {
                    MessageBox.Show("添加失败！", "提示");
                }
            }
            catch
            {
                MessageBox.Show("添加失败，请确认添加的信息是否重复！", "提示");
            }
            finally 
            {
                conn.Close();
            }
         }

6.查询模块

6.1将查询结果显示在类似TextBox控件上

        private void showInfo()
        {
            SqlConnection conn = PubClass.getconnection();
            conn.Open();
            string sqlCmd = "select * from Teachers where ID =" + PubClass.loginID;
            SqlCommand cmd = new SqlCommand(sqlCmd, conn);
            SqlDataReader reader = cmd.ExecuteReader();
            while (reader.Read() == true)
            {
                txtID.Text = reader["ID"].ToString().Trim ();
                txtName.Text = reader["Name"].ToString().Trim ();
                txtPhone.Text = reader["Phone"].ToString().Trim ();
                break;
            }
        }

6.2将查询结果显示在DataGrid上

        private void showInfo()
        {
            SqlConnection conn = PubClass.getconnection();
            string strSql = "select ID,Name,Sex,Age,IdentityCardNumber,Address,Phone,Postcode,StartClassTime,EndClassTime,ClassID,Teacher,Parent,ParentPhone,DormNumber,Intro from Students";
            DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter(strSql, conn);
            conn.Open();
            da.Fill(ds, "Students");
            dataGridView1.DataSource = ds.Tables["Students"].DefaultView;
            lblShowCount.Text = "总共有： " + (dataGridView1.RowCount - 1).ToString() + "条记录";
            for (int i = 0; i < dataGridView1 .Rows.Count ; i++)
            {
                if (i%2==1)
                {
                    dataGridView1.Rows[i].DefaultCellStyle.BackColor = Color.LightYellow;
                }
               
            }
            conn.Close();
        }