Question

我的窗口中有两个Combobox application.1st Combobox显示我已经从xls文件从数据库中获取的国家的城市名称。 Combobox显示这样的城市名称 -

hash = {:h=>1, :k=>2, :v=>3}
hash.each_with_index.detect { |(key,value),index| key == :k }
# => [[:k, 2], 1]
hash.each_with_index.detect { |(key,value),index| key == :k }.last
# => 1

现在我写了一个文本文件，其中包含那些地方的兴趣点列表。我的文本文件看起来像

     Berlin
     Munich 
     Stuttgart //etc.

现在我希望当一个地方出现在第一个组合框中时，所有POI项目将在第二个组合框中以列表形式自动生成，就像我点击柏林第二个组合框将显示一样

Berlin,Berlin Wall,Brandenburg Gate,Reichstag Building
Munich,Nymphenburg palace,Museum Island,Marienplatz
Stuttgart,Old Castle,Staatsgalerie Stuttgart,schlossplatz stuttgart //etc

但我不知道如何继续这样做。

我的代码是 -

ComboBox 1以下面的方式填写

  Berlin Wall
  Brandenburg Gate
  Reichstag Building

然后我从From1.cs调用它，就像那些

 class PlaceList
   {
      public static ComboBox Combo_list = new ComboBox();
      public static DataGridView dataTable = new DataGridView();

      public static void List()
      {

        var startPath = Application.StartupPath;
        string folderName = Path.Combine(startPath, "POI_List");
        System.IO.Directory.CreateDirectory(folderName);
        string SavedfileName = "POI_list.json";
        var Saving_path = Path.Combine(folderName, SavedfileName);

        string fileName = "Zensus_Gemeinden_org.xlsx";
        var path = Path.Combine(startPath, fileName);

        String name = "Gemeinden_31.12.2011_Vergleich";
        String constr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" +
                       path + ";Extended Properties='Excel 12.0 XML;HDR=YES;';";

        OleDbConnection con = new OleDbConnection(constr);
        OleDbCommand oconn = new OleDbCommand("Select [3] as City,[4] as Population, * From [" + name + "$D7:E11300] Where [4] > 10000", con);
        con.Open();

        OleDbDataAdapter sda = new OleDbDataAdapter(oconn);
        DataTable data = new DataTable();

        sda.Fill(data);
        dataTable.DataSource = data;



        for (int i = 0; i < data.Rows.Count; i++)
        {
            Combo_list.Items.Add(data.Rows[i]["City"]);
        }
        string Place_Json = "Place_List:" + JsonConvert.SerializeObject(data, Formatting.Indented);
        File.WriteAllText(Saving_path, Place_Json);

       }
    }
  }

Answer 1

您需要加载文件并逐行在字典中构建一个条目，其中键是带有城市名称的字符串，值是带有POI的字符串列表。然后，当您从组合中选择一个城市时，只需使用该字符串作为搜索词典的关键

例如，这是一个完整的示例，您可以使用LinqPAD进行测试，并展示如何读取您的txt文件并构建一个全局变量，使您的兴趣点按城市名称键入

Form f;
ComboBox cboCities;
ComboBox cboPoi;
Dictionary<string, List<string>> poi = new Dictionary<string, List<string>>();
void Main()
{
    f = new Form();
    cboCities = new ComboBox();
    cboCities.DropDownStyle = ComboBoxStyle.DropDownList;
    cboCities.Items.AddRange(new string[] { "Berlin", "Munich", "Stuttgart"});
    cboCities.SelectedIndexChanged += cboCities_SelectedIndexChanged;
    f.Controls.Add(cboCities);
    cboPoi = new ComboBox();
    cboPoi.Location = new System.Drawing.Point(0, 30);
    f.Controls.Add(cboPoi);
    foreach (string line in File.ReadLines(@"D:\temp\poi.txt"))
    {
        string[] parts = line.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
        poi.Add(parts[0], new List<string>(parts.Skip(1)));
    }
    f.ShowDialog();
}
void cboCities_SelectedIndexChanged(object sender, EventArgs e)
{
    string txt = cboCities.SelectedItem.ToString();
    if (poi.ContainsKey(txt))
    {
        List<string> points = poi[txt];
        cboPoi.Items.Clear();
        cboPoi.Text = string.Empty;
        cboPoi.Items.AddRange(points.ToArray());
    }
}

Answer 2

这是我的编辑答案：

 private void button1_Click(object sender, EventArgs e)
    {

        LoadKeys();

    }
    Dictionary<string, List<string>> poi = new Dictionary<string, List<string>>();
    private void LoadKeys()
    {

       foreach (string line in File.ReadLines("TextFile1.txt"))
                {
                    string[] parts = line.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
                    poi.Add(parts[0], new List<string>());
                    poi[parts[0]] = new List<string>(parts.Skip(1));
                }

    }

    void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedItem != null)
        {
            string txt = comboBox1.SelectedItem.ToString();
            if (poi.ContainsKey(txt))
            {
                List<string> points = poi[txt];
                comboBox2.Items.Clear();
                comboBox2.Items.AddRange(points.ToArray());
            }
        }
    }

如何从文本文件中获取键和值以及在组合框中设置值

2 个答案: