C# 自动完成

Question

我正在尝试向文本框添加自动完成功能，结果来自数据库。它们的格式为

[001] 最后，第一个中间

目前您必须输入 [001]... 才能显示条目。 所以问题是，即使我先输入名字，我也希望它完成。所以如果一个条目是

[001] 史密斯，约翰 D

如果我开始输入 John，那么此条目应该会显示在自动完成的结果中。

目前的代码看起来像

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 是一个包含查询结果的数据集

查询是使用 like 语句的简单搜索查询。如果我们不使用自动完成功能并且只是将结果扔到一个数组中，则会返回正确的结果。

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}'

其中 {0} 是搜索字符串的占位符。

Answer 1

这将为您提供您正在寻找的自动完成行为。

附上的例子是一个完整的工作表，只需要你的数据源和绑定的列名。

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;
}

Answer 2

有两种方法在使用 SQL 的 autoComplete textBox 控件中成功：

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并删除co​​mponent1.designer“根据您给组件类的名称”

c-下载"Download sample - 144.82 KB" 并打开它并从 AutoCompleteTextbox.cs
打开 AutoCompleteTextbox 类 d- 选择所有如图所示并将其复制到当前组件类

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

e- Final - 运行项目并停止以在 toolBox 中查看新的 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;

    }

Answer 3

这是一个继承ComboBox 控件类的实现，而不是用新控件替换整个组合框。当您在文本框中键入时，它会显示自己的下拉列表，但单击以显示下拉列表的处理方式与以前一样（即不使用此代码）。因此，您可以获得适当的本机控制和外观。

如果您想改进它，请使用它，修改它并编辑答案！

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;
    }
}

Answer 4

现有的自动完成功能仅支持按前缀搜索。似乎没有任何体面的方法来覆盖该行为。

有些人通过覆盖OnTextChanged 事件实现了自己的自动完成功能。这可能是你最好的选择。

例如，您可以在TextBox 下方添加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。

作为一个基本示例，这似乎工作得很好：

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;
}

您可以轻松完成更多工作：将文本附加到文本框、捕获其他键盘命令等等。

Answer 5

如果您正在运行该查询（{0} 被输入的字符串替换），您可能需要：

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

LIKE 仍然需要 % 字符...是的，您应该使用参数而不是信任用户的输入 :)

此外，您似乎返回了Name 列，但查询的是Details 列。因此，如果有人输入“John Smith”，如果那不在 Details 列中，您将无法得到您想要的。

Answer 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);