Align Text in Combobox

问题

I want to align my text in combo box so that it will show in the center of combobox tell me how to do this also you can see there is a default border around a combo box when it is in focus how can i remove that border also Kindly solve my two problems Thanks

回答1:

This isn't supported for ComboBox. The exact reasons are lost in the fog of time, ComboBox has been around since the early nineties, but surely has something to do with the awkwardness of getting the text in the textbox portion to line up with the text in the dropdown. Custom drawing with DrawItem cannot solve it either, that only affects the appearance of the dropdown items.

As a possible workaround, you could perhaps do something outlandish like padding the item strings with spaces so they look centered. You'll need TextRenderer.MeasureText() to figure out how many spaces to add for each item.

The "border" you are talking about is not a border, it is the focus rectangle. You can't get rid of that either, Windows refuses to let you create a UI that won't show the control with the focus. Users that prefer the keyboard over the mouse care about that. No workaround for that one.

回答2:

This article will help you: http://blog.michaelgillson.org/2010/05/18/left-right-center-where-do-you-align/

The trick is to set the DrawMode-Property of the ComboBox to OwnerDrawFixed as well as subscribe to its event DrawItem.

Your event should contain the following code:

// Allow Combo Box to center aligned
private void cbxDesign_DrawItem(object sender, DrawItemEventArgs e)
{
  // By using Sender, one method could handle multiple ComboBoxes
  ComboBox cbx = sender as ComboBox;
  if (cbx != null)
  {
    // Always draw the background
    e.DrawBackground();

    // Drawing one of the items?
    if (e.Index >= 0)
    {
      // Set the string alignment.  Choices are Center, Near and Far
      StringFormat sf = new StringFormat();
      sf.LineAlignment = StringAlignment.Center;
      sf.Alignment = StringAlignment.Center;

      // Set the Brush to ComboBox ForeColor to maintain any ComboBox color settings
      // Assumes Brush is solid
      Brush brush = new SolidBrush(cbx.ForeColor);

      // If drawing highlighted selection, change brush
      if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
        brush = SystemBrushes.HighlightText;

      // Draw the string
      e.Graphics.DrawString(cbx.Items[e.Index].ToString(), cbx.Font, brush, e.Bounds, sf);
    }
  }
}

To right align the items you can simply replace StringAlignment.Center with StringAlignment.Far.

回答3:

Set RightToLeft property to true.
It does NOT reverse the sequence of characters. It only right-justifies.

回答4:

Winforms is fairly unflexible when it comes to the customisation of controls. If you are looking for a more customised user experience then I recommend that you look into creating a WPF application which allows you to define custom controls. It will take some work though, so it's only something that you will want to undertake if you really find it to be necessary. Here is a decent site to get you started http://www.wpftutorial.net/

回答5:

you can do something like this by adding space before Display member in your Query

for example :

combobox1.DataSource = Query(Select col1 , ('   '+col2) as Col2 from tableName) 
combobox1.DisplayMember = "Col2";
combobox1.ValueMember = "col1";

回答6:

The post is a bit old but it may be still worth to say:

both requirements are possible for Windows Forms ComboBox:

• Text align center (text area and the dropdown)
  • For the text area, find the Edit control and set the ES_CENTER style for the control.
  • For the dropdown items or the selected item in drop-down mode, to align text to center, just make the control owner-drawn and draw the text at center.
• Get rid of focus rectangle
  • Make the control owner-drawn and just don't draw focus rectangle.

Example

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public class MyComboBox : ComboBox
{
    public MyComboBox()
    {
        DrawMode = DrawMode.OwnerDrawFixed;
    }

    [DllImport("user32.dll")]
    static extern int GetWindowLong(IntPtr hWnd, int nIndex);
    [DllImport("user32.dll")]
    static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
    const int GWL_STYLE = -16;
    const int ES_LEFT = 0x0000;
    const int ES_CENTER = 0x0001;
    const int ES_RIGHT = 0x0002;
    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int Left;
        public int Top;
        public int Right;
        public int Bottom;
        public int Width { get { return Right - Left; } }
        public int Height { get { return Bottom - Top; } }
    }
    [DllImport("user32.dll")]
    public static extern bool GetComboBoxInfo(IntPtr hWnd, ref COMBOBOXINFO pcbi);

    [StructLayout(LayoutKind.Sequential)]
    public struct COMBOBOXINFO
    {
        public int cbSize;
        public RECT rcItem;
        public RECT rcButton;
        public int stateButton;
        public IntPtr hwndCombo;
        public IntPtr hwndEdit;
        public IntPtr hwndList;
    }
    protected override void OnHandleCreated(EventArgs e)
    {
        base.OnHandleCreated(e);
        SetupEdit();
    }
    private int buttonWidth = SystemInformation.HorizontalScrollBarArrowWidth;
    private void SetupEdit()
    {
        var info = new COMBOBOXINFO();
        info.cbSize = Marshal.SizeOf(info);
        GetComboBoxInfo(this.Handle, ref info);
        var style = GetWindowLong(info.hwndEdit, GWL_STYLE);
        style |= 1;
        SetWindowLong(info.hwndEdit, GWL_STYLE, style);
    }
    protected override void OnDrawItem(DrawItemEventArgs e)
    {
        base.OnDrawItem(e);
        e.DrawBackground();
        var txt = "";
        if (e.Index >= 0)
            txt = GetItemText(Items[e.Index]);
        TextRenderer.DrawText(e.Graphics, txt, Font, e.Bounds,
            ForeColor, TextFormatFlags.Left | TextFormatFlags.HorizontalCenter);
    }
}

来源：https://stackoverflow.com/questions/11817062/align-text-in-combobox