C#自动完成

Question

C#自动完成

c#winformsautocomplete

43

我正在尝试为文本框添加自动完成功能，结果来自数据库，格式如下：

[001] 姓, 名中间名

目前必须输入 [001]... 才能显示条目。 问题是，即使我先输入名字，也希望自动完成可以正常工作。所以，如果有一个条目是

[001] 史密斯, 约翰 D

如果我开始输入"约翰"，则此条目应该在自动完成的结果中显示。

目前，代码看起来像这样：

AutoCompleteStringCollection acsc = new AutoCompleteStringCollection();
txtBox1.AutoCompleteCustomSource = acsc;
txtBox1.AutoCompleteMode = AutoCompleteMode.Suggest; 
txtBox1.AutoCompleteSource = AutoCompleteSource.CustomSource; 

....

if (results.Rows.Count > 0)
    for (int i = 0; i < results.Rows.Count && i < 10; i++) 
    {
        row = results.Rows[i];
        acsc.Add(row["Details"].ToString());
    }
}

results是包含查询结果的数据集。

该查询是使用like语句的简单搜索查询。如果不使用自动完成并将结果放入数组中，则返回正确的结果。

有什么建议吗？

编辑：

这是返回结果的查询。

SELECT Name from view_customers where Details LIKE '{0}'

使用 {0} 作为要搜索的字符串的占位符。

- corymathews

乍一看似乎没问题。如果能看到更多的代码，包括查询和“id”的初始化（您是否有两个自动完成框？）将会很有用。 - Steven Richards

好的，我已经更新了查询。我只使用了一个自动完成框。实际上，这个ID在结果中根本没有被使用，它是为以后使用而添加的，因此在此次修改中我将其删除了。对于造成的困惑，非常抱歉。 - corymathews

有一个不错的免费的C# 自动完成控件可用（附带源代码)，很容易修改。 - Jimmy

6个回答

6

如果您决定使用基于用户输入的查询，请确保使用SqlParameters以避免SQL注入攻击。

SqlCommand sqlCommand = new SqlCommand();
sqlCommand.CommandText = "SELECT Name from view_customers where Details LIKE '%" + @SearchParam + "%'";
sqlCommand.Parameters.AddWithValue("@SearchParam", searchParam);

- Jim Scott

4

这里有一种实现方式，该方式继承了ComboBox控件类，而不是用一个新控件替换整个下拉框。当你在文本框中键入时，它会显示自己的下拉列表，但点击以展示下拉列表的方式与之前一样（即不使用此代码）。因此，你将获得适当的原生控件和外观。

如果需要改进，可以使用、修改并编辑此答案！

class ComboListMatcher : ComboBox, IMessageFilter
{
    private Control ComboParentForm; // Or use type "Form" 
    private ListBox listBoxChild;
    private int IgnoreTextChange;
    private bool MsgFilterActive = false;

    public ComboListMatcher()
    {
        // Set up all the events we need to handle
        TextChanged += ComboListMatcher_TextChanged;
        SelectionChangeCommitted += ComboListMatcher_SelectionChangeCommitted;
        LostFocus += ComboListMatcher_LostFocus;
        MouseDown += ComboListMatcher_MouseDown;
        HandleDestroyed += ComboListMatcher_HandleDestroyed;
    }

    void ComboListMatcher_HandleDestroyed(object sender, EventArgs e)
    {
        if (MsgFilterActive)
            Application.RemoveMessageFilter(this);
    }

    ~ComboListMatcher()
    {
    }

    private void ComboListMatcher_MouseDown(object sender, MouseEventArgs e)
    {
        HideTheList();
    }

    void ComboListMatcher_LostFocus(object sender, EventArgs e)
    {
        if (listBoxChild != null && !listBoxChild.Focused)
            HideTheList();
    }

    void ComboListMatcher_SelectionChangeCommitted(object sender, EventArgs e)
    {
        IgnoreTextChange++;
    }

    void InitListControl()
    {
        if (listBoxChild == null)
        {
            // Find parent - or keep going up until you find the parent form
            ComboParentForm = this.Parent;

            if (ComboParentForm != null)
            {
                // Setup a messaage filter so we can listen to the keyboard
                if (!MsgFilterActive)
                {
                    Application.AddMessageFilter(this);
                    MsgFilterActive = true;
                }

                listBoxChild = listBoxChild = new ListBox();
                listBoxChild.Visible = false;
                listBoxChild.Click += listBox1_Click;
                ComboParentForm.Controls.Add(listBoxChild);
                ComboParentForm.Controls.SetChildIndex(listBoxChild, 0); // Put it at the front
            }
        }
    }


    void ComboListMatcher_TextChanged(object sender, EventArgs e)
    {
        if (IgnoreTextChange > 0)
        {
            IgnoreTextChange = 0;
            return;
        }

        InitListControl();

        if (listBoxChild == null)
            return;

        string SearchText = this.Text;

        listBoxChild.Items.Clear();

        // Don't show the list when nothing has been typed
        if (!string.IsNullOrEmpty(SearchText))
        {
            foreach (string Item in this.Items)
            {
                if (Item != null && Item.Contains(SearchText, StringComparison.CurrentCultureIgnoreCase))
                    listBoxChild.Items.Add(Item);
            }
        }

        if (listBoxChild.Items.Count > 0)
        {
            Point PutItHere = new Point(this.Left, this.Bottom);
            Control TheControlToMove = this;

            PutItHere = this.Parent.PointToScreen(PutItHere);

            TheControlToMove = listBoxChild;
            PutItHere = ComboParentForm.PointToClient(PutItHere);

            TheControlToMove.Show();
            TheControlToMove.Left = PutItHere.X;
            TheControlToMove.Top = PutItHere.Y;
            TheControlToMove.Width = this.Width;

            int TotalItemHeight = listBoxChild.ItemHeight * (listBoxChild.Items.Count + 1);
            TheControlToMove.Height = Math.Min(ComboParentForm.ClientSize.Height - TheControlToMove.Top, TotalItemHeight);
        }
        else
            HideTheList();
    }

    /// <summary>
    /// Copy the selection from the list-box into the combo box
    /// </summary>
    private void CopySelection()
    {
        if (listBoxChild.SelectedItem != null)
        {
            this.SelectedItem = listBoxChild.SelectedItem;
            HideTheList();
            this.SelectAll();
        }
    }

    private void listBox1_Click(object sender, EventArgs e)
    {
        var ThisList = sender as ListBox;

        if (ThisList != null)
        {
            // Copy selection to the combo box
            CopySelection();
        }
    }

    private void HideTheList()
    {
        if (listBoxChild != null)
            listBoxChild.Hide();
    }

    public bool PreFilterMessage(ref Message m)
    {
        if (m.Msg == 0x201) // Mouse click: WM_LBUTTONDOWN
        {
            var Pos = new Point((int)(m.LParam.ToInt32() & 0xFFFF), (int)(m.LParam.ToInt32() >> 16));

            var Ctrl = Control.FromHandle(m.HWnd);
            if (Ctrl != null)
            {
                // Convert the point into our parent control's coordinates ...
                Pos = ComboParentForm.PointToClient(Ctrl.PointToScreen(Pos));

                // ... because we need to hide the list if user clicks on something other than the list-box
                if (ComboParentForm != null)
                {
                    if (listBoxChild != null &&
                        (Pos.X < listBoxChild.Left || Pos.X > listBoxChild.Right || Pos.Y < listBoxChild.Top || Pos.Y > listBoxChild.Bottom))
                    {
                        this.HideTheList();
                    }
                }
            }
        }
        else if (m.Msg == 0x100) // WM_KEYDOWN
        {
            if (listBoxChild != null && listBoxChild.Visible)
            {
                switch (m.WParam.ToInt32())
                {
                    case 0x1B: // Escape key
                        this.HideTheList();
                        return true;

                    case 0x26: // up key
                    case 0x28: // right key
                        // Change selection
                        int NewIx = listBoxChild.SelectedIndex + ((m.WParam.ToInt32() == 0x26) ? -1 : 1);

                        // Keep the index valid!
                        if (NewIx >= 0 && NewIx < listBoxChild.Items.Count)
                            listBoxChild.SelectedIndex = NewIx;
                        return true;

                    case 0x0D: // return (use the currently selected item)
                        CopySelection();
                        return true;
                }
            }
        }

        return false;
    }
}

- noelicus

这个不是简单地从ComboBox继承而来。它有一些问题：ComboParentForm = this.Parent(); 应该改为 this.Parent;，ContainsNoCase 看起来像是一个自定义的扩展方法，IntEx.Limit 看起来像是一个自定义的帮助类。 - Stuart Grassie

1

谢谢指出这些问题 - 我已经相应地更新了。更清楚了吗？希望能帮到你。 - noelicus

谢谢！这是我见过的最好的实现。我在代码中发现了一些问题，同时也对其进行了简化。https://yadi.sk/i/SCrni3ZlqzoKr - Dmytro Ovdiienko

a) 你需要两个using语句。using System.Windows.Forms; 和 using System.Drawing;，一个用于ComboBox，一个用于Point。 b) 这行代码if (Item != null && Item.Contains(SearchText, StringComparison.CurrentCultureIgnoreCase))不起作用，没有像那样带有两个参数的Contains方法。有一个带有一个参数的字符串的Contains方法。你可以使用if (Item != null && Item.ToLower().Contains(SearchText.ToLower()))，这可能是你想要的。 - barlop

我有一个相对愚蠢的问题。如何向列表中添加内容？ - barlop

listBoxChild.Items.Add() ... 这个在示例中被省略了，因为如何公开它取决于您！ - noelicus

1

这将为您提供所需的自动完成行为。

附带的示例是一个完整的工作表单，只需要您的数据源和绑定列名称。

using System;
using System.Data;
using System.Windows.Forms;

public partial class frmTestAutocomplete : Form
{

    private DataTable maoCompleteList; //the data table from your data source
    private string msDisplayCol = "name"; //displayed text
    private string msIDcol = "id"; //ID or primary key

    public frmTestAutocomplete(DataTable aoCompleteList, string sDisplayCol, string sIDcol)
    {
        InitializeComponent();

        maoCompleteList = aoCompleteList
        maoCompleteList.CaseSensitive = false; //turn off case sensitivity for searching
        msDisplayCol = sDisplayCol;
        msIDcol = sIDcol;
    }

    private void frmTestAutocomplete_Load(object sender, EventArgs e)
    {

            testCombo.DisplayMember = msDisplayCol;
            testCombo.ValueMember = msIDcol; 
            testCombo.DataSource = maoCompleteList;
            testCombo.SelectedIndexChanged += testCombo_SelectedIndexChanged;
            testCombo.KeyUp += testCombo_KeyUp; 

    }


    private void testCombo_KeyUp(object sender, KeyEventArgs e)
    {
        //use keyUp event, as text changed traps too many other evengts.

        ComboBox oBox = (ComboBox)sender;
        string sBoxText = oBox.Text;

        DataRow[] oFilteredRows = maoCompleteList.Select(MC_DISPLAY_COL + " Like '%" + sBoxText + "%'");

        DataTable oFilteredDT = oFilteredRows.Length > 0
                                ? oFilteredRows.CopyToDataTable()
                                : maoCompleteList;

        //NOW THAT WE HAVE OUR FILTERED LIST, WE NEED TO RE-BIND IT WIHOUT CHANGING THE TEXT IN THE ComboBox.

        //1).UNREGISTER THE SELECTED EVENT BEFORE RE-BINDING, b/c IT TRIGGERS ON BIND.
        testCombo.SelectedIndexChanged -= testCombo_SelectedIndexChanged; //don't select on typing.
        oBox.DataSource = oFilteredDT; //2).rebind to filtered list.
        testCombo.SelectedIndexChanged += testCombo_SelectedIndexChanged;


        //3).show the user the new filtered list.
        oBox.DroppedDown = true; //do this before repainting the text, as it changes the dropdown text.

        //4).binding data source erases text, so now we need to put the user's text back,
        oBox.Text = sBoxText;
        oBox.SelectionStart = sBoxText.Length; //5). need to put the user's cursor back where it was.


    }

    private void testCombo_SelectedIndexChanged(object sender, EventArgs e)
    {

        ComboBox oBox = (ComboBox)sender;

        if (oBox.SelectedValue != null)
        {
            MessageBox.Show(string.Format(@"Item #{0} was selected.", oBox.SelectedValue));
        }
    }
}

//=====================================================================================================
//      code from frmTestAutocomplete.Designer.cs
//=====================================================================================================
partial class frmTestAutocomplete
{
    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.testCombo = new System.Windows.Forms.ComboBox();
        this.SuspendLayout();
        // 
        // testCombo
        // 
        this.testCombo.FormattingEnabled = true;
        this.testCombo.Location = new System.Drawing.Point(27, 51);
        this.testCombo.Name = "testCombo";
        this.testCombo.Size = new System.Drawing.Size(224, 21);
        this.testCombo.TabIndex = 0;
        // 
        // frmTestAutocomplete
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 273);
        this.Controls.Add(this.testCombo);
        this.Name = "frmTestAutocomplete";
        this.Text = "frmTestAutocomplete";
        this.Load += new System.EventHandler(this.frmTestAutocomplete_Load);
        this.ResumeLayout(false);

    }

    #endregion

    private System.Windows.Forms.ComboBox testCombo;
}

- mike

0

如果你正在运行该查询（其中{0}被替换为输入的字符串），你可能需要：

SELECT Name from view_customers where Details LIKE '%{0}%'

LIKE 还需要 % 字符... 而且，你应该使用参数而不是信任用户的输入 :)

另外，你似乎返回了 Name 列，但查询的是 Details 列。所以如果有人输入了 "John Smith"，如果它不在 Details 列中，你将得不到想要的结果。

- Damovisa

我注意到你选择了“Name”，但是你正在查询“Details” - 这不是问题吧？ - Damovisa

啊，当我发布问题时，名称更改让我有点困惑。我只是为了更容易理解而更改了名称。我以为我很一致，但我会进行修正。 - corymathews

-1

使用 SQL 成功实现自动完成文本框控件的两种方法：

但您应该执行以下操作：

a- 创建新项目

b- 将组件类添加到项目中，并删除 component1.designer "根据您给组件类的名称"

c- 下载 "示例下载 - 144.82 KB" 并打开它，从 AutoCompleteTextbox.cs 中打开 AutoCompleteTextbox 类
d- 如图所示选择全部内容并将其复制到当前组件类

http://i.stack.imgur.com/oSqCa.png

e-Final-运行项目并停止以查看工具箱中的新AutoCompleteTextbox。

现在您可以添加以下两种方法，您可以使用它们来使用SQL

1-在Form_Load中

private void Form1_Load(object sender, EventArgs e)
  {            
   SqlConnection cn = new SqlConnection(@"server=.;database=My_dataBase;integrated security=true");
   SqlDataAdapter da = new SqlDataAdapter(@"SELECT [MyColumn] FROM [my_table]", cn);
   DataTable dt = new DataTable();
   da.Fill(dt);

   List<string> myList = new List<string>();
    foreach (DataRow row in dt.Rows)
       {
          myList.Add((string)row[0]);
       }

   autoCompleteTextbox1.AutoCompleteList = myList;
    }

2- 在TextChanged事件中

 private void autoCompleteTextbox_TextChanged(object sender, EventArgs e)
        {           
         SqlConnection cn = new SqlConnection(@"server=.;database=My_dataBase;integrated security=true");
         SqlDataAdapter da = new SqlDataAdapter(@"SELECT [MyColumn] FROM [my_table]", cn);
         DataTable dt = new DataTable();
         da.Fill(dt);

     List<string> myList = new List<string>();
      foreach (DataRow row in dt.Rows)
        {
          myList.Add((string)row[0]);
        }

   autoCompleteTextbox2.AutoCompleteList = myList;

    }

- Sherif Hamdy

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Steven Richards · Accepted Answer

现有的自动完成功能只支持按前缀搜索。似乎没有什么好方法可以覆盖这种行为。

一些人通过覆盖“OnTextChanged”事件来实现自己的自动完成功能。这可能是您最好的选择。

例如，您可以在文本框下方添加一个ListBox，并将其默认可见性设置为false。然后，您可以使用TextBox的OnTextChanged事件和ListBox的SelectedIndexChanged事件来显示和选择项目。

这似乎作为一个基本示例相当好用：

public Form1()
{
    InitializeComponent();


    acsc = new AutoCompleteStringCollection();
    textBox1.AutoCompleteCustomSource = acsc;
    textBox1.AutoCompleteMode = AutoCompleteMode.None;
    textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
}

private void button1_Click(object sender, EventArgs e)
{
    acsc.Add("[001] some kind of item");
    acsc.Add("[002] some other item");
    acsc.Add("[003] an orange");
    acsc.Add("[004] i like pickles");
}

void textBox1_TextChanged(object sender, System.EventArgs e)
{
    listBox1.Items.Clear();
    if (textBox1.Text.Length == 0)
    {
    hideResults();
    return;
    }

    foreach (String s in textBox1.AutoCompleteCustomSource)
    {
    if (s.Contains(textBox1.Text))
    {
        Console.WriteLine("Found text in: " + s);
        listBox1.Items.Add(s);
        listBox1.Visible = true;
    }
    }
}

void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{
    textBox1.Text = listBox1.Items[listBox1.SelectedIndex].ToString();
    hideResults();
}

void listBox1_LostFocus(object sender, System.EventArgs e)
{
    hideResults();
}

void hideResults()
{
    listBox1.Visible = false;
}

你可以很轻松地做更多的事情：向文本框追加文本，捕获额外的键盘命令等等。