C~*自动完成

现有的自动完成功能只支持按前缀搜索。似乎没有任何体面的方法来推翻这种行为。

有些人通过重写 OnTextChanged 事件。这可能是你最好的选择。

例如,可以添加 ListBox 就在下面 TextBox 并将其默认可见性设置为false。然后你可以使用 文本更改 事件 文本框 以及 SelectedIndexChanged 事件 列表框 显示和选择项目。

这似乎是一个很好的基本例子:

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;
}

不用太费劲,您可以做很多事情:将文本附加到文本框中,捕获其他键盘命令,等等。

如果决定使用基于用户输入的查询,请确保使用sqlparameters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);

下面是一个继承 ComboBox 控件类,而不是用新控件替换整个组合框。当您在文本框中键入内容时,它会显示自己的下拉列表,但单击以显示下拉列表会像以前一样处理(即,不使用此代码)。因此,您可以获得适当的本地控制和外观。

如果您想改进,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;
    }
}

如果您正在运行该查询(使用 {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 % 性格…是的,您应该使用参数而不是信任用户的输入:)

此外,您似乎还返回了 Name 列,但查询 Details 列。如果有人输入“john smith”,如果不在 细节 列你将得不到你想要的。

这将为您提供所需的自动完成行为。

附加的示例是一个完整的工作表单,只需要您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;
    private const string MC_DISPLAY_COL = "name";
    private const string MC_ID_COL = "id";

    public frmTestAutocomplete()
    {
        InitializeComponent();
    }

    private void frmTestAutocomplete_Load(object sender, EventArgs e)
    {
        using (clsDataAccess oData = new clsDataAccess())
        {

            maoCompleteList = oData.PurificationRuns;
            maoCompleteList.CaseSensitive = false; //turn off case sensitivity for searching

            testCombo.DisplayMember = MC_DISPLAY_COL;
            testCombo.ValueMember = MC_ID_COL; 
            testCombo.DataSource = GetDataTableFromDatabase();
            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;
}

有两种方法在使用SQL的自动完成文本框控件中成功:

但您应该做以下操作:

A-创建新项目

B-将组件类添加到项目并删除component1.designer“根据您给组件类的名称”

C下载 "Download sample - 144.82 KB" 然后打开它并从autocompletetextbox.cs打开autocompletetextbox类。
d-选择图像中所示的全部,并将其复制到当前组件类

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

e-最终-运行项目并停止以在工具箱中查看新的自动完成文本框。

现在您可以添加以下两个方法,您可以将SQL与它们一起使用

1英寸负荷

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;

    }