小菜之智能客户端（４）演化TaskVision,添加项目

我们在前一篇的基础上添加功能，允许添加项目。
从Web服务DataService.asmx开始：添加Web方法InsertProject()

using System;
using System.Data;
using System.Data.SqlClient;
using System.Web;
using System.Collections;
using System.Web.Services;
using System.Web.Services.Protocols;
/**//// <summary>
/// DataService 的摘要说明
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class DataService : System.Web.Services.WebService
{
    private SqlConnection _conn;
    private SqlDataAdapter _daProjects;
    private SqlCommand _selectProjectsCommand;

    public DataService()
    {
        //如果使用设计的组件，请取消注释以下行 
        //InitializeComponent(); 
        _conn = new SqlConnection("Data Source=(local);Initial Catalog=TaskVision;User ID=sa;Password=password;");
        
        _daProjects = new SqlDataAdapter();

        _selectProjectsCommand = new SqlCommand();
        _selectProjectsCommand.Connection = _conn;
        _selectProjectsCommand.CommandText = "SELECT ProjectID, ProjectName, ProjectDescription, DateCreated FROM Projects WHERE (IsDeleted = 0)";
        
        _daProjects.SelectCommand = _selectProjectsCommand;
    }

    [WebMethod]
    public DataSetProjects GetProjects()
    {
        DataSetProjects ds = new DataSetProjects();
        _daProjects.Fill(ds.Projects);
        return ds;
    }

    [WebMethod]
    public int InsertProject(string projectName, string projectDescription)
    {
        SqlCommand insertProjectCommand = new SqlCommand();
        insertProjectCommand.Connection = _conn;
        insertProjectCommand.CommandText = "INSERT INTO Projects(ProjectName,ProjectDescription) VALUES(@ProjectName,@ProjectDescription);SELECT SCOPE_IDENTITY()";
        
        SqlParameter parmProjectName = new SqlParameter("@ProjectName", SqlDbType.VarChar, 20);
        parmProjectName.Value = projectName;
        SqlParameter parmProjectDescription = new SqlParameter("@ProjectDescription", SqlDbType.VarChar, 100);
        parmProjectDescription.Value = projectDescription;
        
        insertProjectCommand.Parameters.Add(parmProjectName);
        insertProjectCommand.Parameters.Add(parmProjectDescription);

        object projectID;

        try
        {
            _conn.Open();
            projectID = insertProjectCommand.ExecuteScalar();
        }
        finally
        {
            _conn.Close();
        }

        if (projectID == null)
        {
            return -1;
        }
        else
        {
            return Convert.ToInt32(projectID);
        }
    }
}

相应的修改本地应用程序的DataLayer：

using System;
using TaskVision.DataWS;

namespace TaskVision
{
    public enum WebServicesExceptionType
    {
        WebException = 0,
        SoapException = 1,
        Exception = 2,
        None = 3
    }

    public class DataLayer
    {
        private DataService _dataService;

        private DataSetProjects _dsProjects = new DataSetProjects();

        public DataSetProjects.ProjectsDataTable Projects
        {
            get
            {
                return _dsProjects.Projects;
            }
        }

        public DataLayer()
        {
            _dataService = GetWebServiceReference();
        }

        public WebServicesExceptionType GetProjects()
        {
            DataSetProjects dsProjects = null;

            WebServicesExceptionType exceptionType = WebServicesExceptionType.None;

            try
            {
                dsProjects = _dataService.GetProjects();
            }
            catch (System.Net.WebException)
            {
                exceptionType = WebServicesExceptionType.WebException;
            }
            catch (System.Web.Services.Protocols.SoapException)
            {
                exceptionType = WebServicesExceptionType.SoapException;
            }
            catch (System.Exception)
            {
                exceptionType = WebServicesExceptionType.Exception;
            }

            if (dsProjects != null)
            {
                _dsProjects.Clear();
                _dsProjects.Merge(dsProjects);
            }

            return exceptionType;
        }

        public WebServicesExceptionType InsertProject(ref int projectID, string projectName, string projectDescription)
        {
            WebServicesExceptionType exceptionType = WebServicesExceptionType.None;

            try
            {
                projectID = _dataService.InsertProject(projectName, projectDescription);
            }
            catch (System.Net.WebException)
            {
                exceptionType = WebServicesExceptionType.WebException;
            }
            catch (System.Web.Services.Protocols.SoapException)
            {
                exceptionType = WebServicesExceptionType.SoapException;
            }
            catch (System.Exception)
            {
                exceptionType = WebServicesExceptionType.Exception;
            }

            return exceptionType;
        }

        private DataService GetWebServiceReference()
        {
            DataService dataService = new DataService();

            string urlSetting = System.Configuration.ConfigurationManager.AppSettings["DataServiceUrl"];
            
            if (urlSetting != null)
            {
                dataService.Url = urlSetting;
            }
            else
            {
                dataService.Url = "http://localhost/TaskVisionWS/DataService.asmx";
            }

            return dataService;
        }
    }
}

从上面的代码大家可以很直观的看到重复的部份代码：catch(WebException){}catch(SoapException){}catch(Exception){}
在软件的设计原则有好多，不过在真正的开发中很容易被大家忘的一干二净，这时记住一点就可以了：减少重复代码。

改进后的DataLayer代码：

using System;
using TaskVision.DataWS;

namespace TaskVision
{
    public enum WebServicesExceptionType
    {
        WebException = 0,
        SoapException = 1,
        Exception = 2,
        None = 3
    }

    public class DataLayer
    {
        private DataService _dataService;

        private DataSetProjects _dsProjects = new DataSetProjects();

        public DataSetProjects.ProjectsDataTable Projects
        {
            get
            {
                return _dsProjects.Projects;
            }
        }

        public DataLayer()
        {
            _dataService = GetWebServiceReference();
        }

        public WebServicesExceptionType GetProjects()
        {
            DataSetProjects dsProjects = null;

            WebServicesExceptionType exceptionType = WebServicesExceptionType.None;

            try
            {
                dsProjects = _dataService.GetProjects();
            }
            catch (System.Exception ex)
            {
                exceptionType = HandleException(ex);
            }
            if (dsProjects != null)
            {
                _dsProjects.Clear();
                _dsProjects.Merge(dsProjects);
            }

            return exceptionType;
        }

        public WebServicesExceptionType InsertProject(ref int projectID, string projectName, string projectDescription)
        {
            WebServicesExceptionType exceptionType = WebServicesExceptionType.None;

            try
            {
                projectID = _dataService.InsertProject(projectName, projectDescription);
            }
            catch (System.Exception ex)
            {
                exceptionType = HandleException(ex);
            }

            return exceptionType;
        }

        private WebServicesExceptionType HandleException(Exception ex)
        {
            if (ex is System.Net.WebException)
                return WebServicesExceptionType.WebException;
            else if (ex is System.Web.Services.Protocols.SoapException)
                return WebServicesExceptionType.SoapException;
            else
                return WebServicesExceptionType.Exception;
        }

        private DataService GetWebServiceReference()
        {
            DataService dataService = new DataService();

            string urlSetting = System.Configuration.ConfigurationManager.AppSettings["DataServiceUrl"];
           
            if (urlSetting != null)
            {
                dataService.Url = urlSetting;
            }
            else
            {
                dataService.Url = "http://localhost/TaskVisionWS/DataService.asmx";
            }

            return dataService;
        }
    }
}

接着我们新建一个窗体：AddProjectForm
 
TextBox：txtProjectName
TextBox：txtProjectDescription
Button：btnOk
Button：btnCancel

我们在主窗体中显示它：
 

private void miManageAddProject_Click(object sender, System.EventArgs e)
{
    AddProjectForm addProjectForm = new AddProjectForm(_dataLayer);
    addProjectForm.ShowDialog();
}

AddProjectForm窗体的代码如下：

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

namespace TaskVision
{
    public partial class AddProjectForm : Form
    {
        private DataLayer _dataLayer;

        public AddProjectForm(DataLayer dataLayer)
        {
            InitializeComponent();

            _dataLayer = dataLayer;
        }

        private void btnOk_Click(object sender, EventArgs e)
        {
            if (txtProjectName.Text.Trim() != string.Empty && txtProjectDescription.Text.Trim() != string.Empty)
            {

                int projectID = -1;
                WebServicesExceptionType exceptionType = _dataLayer.InsertProject(ref projectID, txtProjectName.Text.Trim(), txtProjectDescription.Text.Trim());

                // if database update was successful add the project to our local data
                if (exceptionType == WebServicesExceptionType.None)
                {
                    DataWS.DataSetProjects.ProjectsRow dr = _dataLayer.Projects.NewProjectsRow();
                    dr.ProjectID = projectID;
                    dr.ProjectName = txtProjectName.Text.Trim();
                    dr.ProjectDescription = txtProjectDescription.Text.Trim();
                    dr.DateCreated = DateTime.Now;
                    _dataLayer.Projects.Rows.Add(dr);
                }
                else
                {
                    MessageBox.Show("添加新项目失败", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    this.DialogResult = DialogResult.None;
                }
            }
            else
            {
                this.DialogResult = DialogResult.None;
            }

            this.Close();
        }

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

测试：

点击添加。
 
添加成功。

好了这篇就说到这了，下篇会进入重点，通过ProjectID获取任务.