Question

我正在尝试创建自定义DataGridViewButtonCell，以便在单击后下载文件。该类完美无缺，但在使用rows.add（）方法时不会将自身添加到DataGridView中。它似乎只是为标签使用ToString（）方法，然后从CellTemplate创建自己的。

特定列的类型是DataGridViewDownloadColumn。我还运行测试输出网格视图中保存的值，它是正确实例化的类。

这是我没有布局信息的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using MS.Internal.Xml;
using System.Net;

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

        private void button1_Click(object sender, EventArgs e)
        {
            XmlReader objReader = XmlReader.Create("http://revision3.com/filmriot/feed/Xvid-Large");

            while (objReader.ReadToFollowing("enclosure"))
            {
                objReader.MoveToFirstAttribute();

                Uri objURI = new Uri(objReader.ReadContentAsString());
                string[] objString = objURI.Segments;

                DownloadButton objDL = new DownloadButton(objURI, objString[objString.Length - 1]);

                this.dataGridView1.Rows.Add(false, "Hello!", objDL);
            }
        }
    }

    public class DataGridViewDownloadColumn : DataGridViewButtonColumn
    {
        public DataGridViewDownloadColumn()
        {
            CellTemplate = new DownloadButton();
        }
    }

    class DownloadButton : DataGridViewButtonCell
    {
        WebClient objDownloader = new WebClient();
        Uri     fileURL;
        string  strSavePath;

        public DownloadButton()
        {

        }

        public DownloadButton(Uri fileURI, string strFilename) : base()
        {
            objDownloader.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgChanged);

            this.fileURL     = fileURI;
            this.strSavePath = strFilename;

            this.Value = "Download";
        }

        protected override void OnClick(DataGridViewCellEventArgs e)
        {
            // If it's downloading, cancel the download
            if (objDownloader.IsBusy)
            {
                objDownloader.CancelAsync();
                this.Value = "Download";
            }
            else
                objDownloader.DownloadFileAsync(fileURL, strSavePath);

            base.OnClick(e);
        }

        void ProgChanged(object sender, DownloadProgressChangedEventArgs e)
        {
            this.Value = e.ProgressPercentage + "%";
        }

        public override string ToString()
        {
            return
                "Download Button:\n" +
                this.fileURL.ToString();
        }
    }
}

我一直在和这个垃圾斗争几个小时。任何帮助表示赞赏。

Answer 1

似乎由于某种原因，如果使用独立构造函数创建自定义对象，datagridview.rows.add（对象列表）不会删除它。您需要做的是创建一个新行，单独添加单元格，然后将该行放入列表中。

        while (objReader.ReadToFollowing("enclosure"))
        {
            objReader.MoveToFirstAttribute();

            Uri objURI = new Uri(objReader.ReadContentAsString());
            string[] objString = objURI.Segments;
            string strFileName = objString[objString.Length - 1];

            // No string constructor?! What the crap?
            DataGridViewTextBoxCell objFileCell = new DataGridViewTextBoxCell();
            objFileCell.Value = strFileName;

            DataGridViewRow objRow = new DataGridViewRow();
            objRow.Cells.Add(new DataGridViewCheckBoxCell(false));
            objRow.Cells.Add(objFileCell);
            objRow.Cells.Add(new DownloadButton(objURI, strFileName));
            this.dataGridView1.Rows.Add(objRow);
        }

C＃DataGridView Add使用ToString（）？

1 个答案: