玩转控件:封装Dev的SearchLookupEdit

鸣谢

随着前面几个章节对控件封装与扩展的分享，不少小伙伴儿们在作者公众号上反馈，并联系作者，表示通过这些系列和源码能学到不少细节上的东西，并运用到了自己的实际项目当中，也有不少伙伴儿反馈更好更优的处理方式。作者在此感谢大家的陪伴与探讨，希望能与大家一起学习，一起进步。

工欲善其事必先利其器

公众号反馈最多的是《玩转控件:封装Dev的LabelControl和TextEdit》，表示运用到自己实际项目后，确实大大减少了自己的工作量，并希望能有更多这种类型的博文。为了满足小伙伴儿的心愿，作者后续会分享更多自己实际项目运用到的小技巧，希望能对更多小伙伴儿有更多的帮助和启发。最后，也希望小伙伴儿们能从作者分享对不同类型控件的封装中举一反三，扩展满足自己实际业务的插件。有好的想法，别忘记分享给作者哦，三人行，必有我师嘛~

Talk is Cheap

废话不多说，今天作者要分享的也是作者实际项目中遇到的问题——有数据源的下拉搜索框。不少大的企业反馈，公司职员比较多，数据量比较大，鼠标下拉寻找太过繁琐和耗时，能不能提供个更优的处理方式。经过作者一番思索，以迅雷不及掩耳盗铃响叮当之势就找到了符合客户的处理方式——就是Dev的SearchLookupEdit。

大家也可以直接用Dev的SearchLookupEdit控件，效果还不错，当然为了方便起见，减少自己的操作量，也可以模仿《玩转控件:封装Dev的LabelControl和TextEdit》一样，自己根据实际情况做个封装，来吧！作者陪大家一起重温下封装的乐趣。

Show me the Code

　　和往常一样，新建一个类用来封装和扩展自己实际要用到的属性和事件：

 public partial class KzxSearchComboboxEdit : KzxBaseControl

初始化的时候，就可以封装好自己要用到的事件：

public KzxSearchComboboxEdit()
    {
        InitializeComponent();

        this.ValueControl.QueryPopUp += new CancelEventHandler(lookUpEdit_QueryPopUp);
        this.ValueControl.Closed += new ClosedEventHandler(lookUpEdit_Closed);

        this.CaptionControl.AutoSizeMode = LabelAutoSizeMode.Vertical;
        this.CaptionControl.SizeChanged += new EventHandler(SetSize);
        this.ValueControl.Enter -= new EventHandler(ValueControl_Enter);
        this.ValueControl.Enter += new EventHandler(ValueControl_Enter);

        this._SearchLookUpEditView.FocusRectStyle = DevExpress.XtraGrid.Views.Grid.DrawFocusRectStyle.RowFocus;
        this._SearchLookUpEditView.Name = "gridLookUpEdit1View";
        this._SearchLookUpEditView.OptionsSelection.EnableAppearanceFocusedCell = false;
        this._SearchLookUpEditView.OptionsView.ShowGroupPanel = false;
        this.ValueControl.Properties.PopupFormSize = new System.Drawing.Size((int)(this.ValueControl.Width * 2), (int)(this.ValueControl.Width * 1.5));

        if (this.DesignMode == true)
        {
            this.Size = new Size(284, 21);
        }
    }

把自己实际需要用到的属性做好封装，举个栗子：

 private int _ItemIndex = -1;
  /// <summary>
  /// 选中项的下标
  /// </summary>
  [Category("自定义"), Description("ItemIndex,选中项的下标"), Browsable(false)]
  [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  [McDisplayName("ItemIndex")]
  public int ItemIndex
  {
      get
      {
          return this._ItemIndex;
      }
      protected set
      {
          this._ItemIndex = value;
      }
  }
  
  private DataRow _CurrentItem = null;
  /// <summary>
  /// 选中项的DataRow对象
  /// </summary>
  [Category("自定义"), Description("CurrentItem,选中项的DataRow对象"), Browsable(false)]
  [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  [McDisplayName("CurrentItem")]
  public DataRow CurrentItem
  {
      get
      {
          return this._CurrentItem;
      }
      protected set
      {
          this._CurrentItem = value;
      }
  }
  
  
  private DataSet _BillDataSet = new DataSet();
  /// <summary>
  /// 单据的数据源
  /// </summary>
  [Category("自定义"), Description("BillDataSet,单据的数据源"), Browsable(false)]
  [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  [McDisplayName("BillDataSet")]
  public DataSet BillDataSet
  {
      get
      {
          return this._BillDataSet;
      }
      set
      {
          this._BillDataSet = value;
      }
  }
  
  /// <summary>
  /// 没有多语言的情况下的默认显示标题
  /// </summary>
  [Category("多语言"), Description("DesigeCaption,没有多语言的情况下的默认显示标题"), Browsable(true)]
  [McDisplayName("DesigeCaption")]
  public override string DesigeCaption
  {
      get
      {
          return this.CaptionControl.Text.Trim();
      }
      set
      {
          this.CaptionControl.Text = value;
      }
  }

也可以根据自己喜好（当然是符合客户习惯的），画蛇添足：

private bool _IsNull = true;
  /// <summary>
  /// 可空性
  /// </summary>
  [Category("验证"), Description("IsNull,可空性"), Browsable(true)]
  [McDisplayName("IsNull")]
  public override bool IsNull
  {
      get
      {
          SetBackColor();
          return this._IsNull;
      }
      set
      {
          this._IsNull = value;
          SetBackColor();
      }
  }
  ...
    /// <summary>
    /// 设置背景色
    /// </summary>
    private void SetBackColor()
    {
        if (this.ValueControl.Properties.ReadOnly == true)
        {
            this.ValueControl.BackColor = Color.FromArgb(242, 242, 243);
        }
        else
        {
            if (this._IsNull.Equals(true) == false)
            {
                this.ValueControl.BackColor = Color.Yellow;
            }
            else
            {
                this.ValueControl.BackColor = this._TextBackColor;
            }
        }
    }

当设置控件必填的时候，设置控件的背景色用于区分，具体效果如图：

封装好控件取值，填充值的方法，以及控件数据源绑定的方法（具体根据自己实际项目应用为准，此处只是举个栗子）

/// <summary>
/// 取控件的值
/// </summary>
/// <return>Object</return>
public override object GetValue()
{
    DataRowView rowview = null;
    BindingSource bs = null;
    object v = null;

    v = this.ValueControl.EditValue == null || this.ValueControl.EditValue == DBNull.Value ? string.Empty : this.ValueControl.EditValue.ToString();
    return v;
}

/// <summary>
/// 设置控件的值
/// </summary>
/// <param name="value">控件的值</param>
/// <return>int</return>
public override int SetValue(object value)
{
    this.ValueControl.EditValue = value == null || value == DBNull.Value ? string.Empty : value;
    return 1;
}


/// <summary>
/// 设置数据绑定
/// </summary>
/// <param name="binding">数据绑定对象</param>
/// <return>int</return>
public override int SetDataBinding(object binding)
{
    this.BindingObject = this.ValueControl.DataBindings.Add("EditValue", binding, this.Field, true, DataSourceUpdateMode.OnValidation, string.Empty, this.FormatString);
    SetColumnDisplayFormat();
    if (binding is BindingSource)
    {
        int maxlength = 0;
        if (((BindingSource)binding).DataSource is DataView)
        {
            if (((DataView)(((BindingSource)binding).DataSource)).Table.Columns[this.Field].DataType == typeof(string))
            {
                maxlength = ((DataView)(((BindingSource)binding).DataSource)).Table.Columns[this.Field].MaxLength;
                if (maxlength >= 0)
                {
                    this.MaxLength = maxlength;
                }
            }
        }
        else if (((BindingSource)binding).DataSource is DataTable)
        {
            if (((DataTable)(((BindingSource)binding).DataSource)).Columns[this.Field].DataType == typeof(string))
            {
                maxlength = ((DataTable)(((BindingSource)binding).DataSource)).Columns[this.Field].MaxLength;
                if (maxlength >= 0)
                {
                    this.MaxLength = maxlength;
                }
            }
        }
    }
    return 1;
}

/// <summary>
/// 设置下拉框的数据源
/// </summary>
/// <param name="binding">下拉框的数据源</param>
/// <param name="displayMember">显示值字段名</param>
/// <param name="valueMember">实际值字段名</param>
/// <returns>int</returns>
public override int SetSourceTableBinding(object binding, string displayMember, string valueMember)
{
    this.DisplayMemberPath = displayMember;
    this.SelectedValuePath = valueMember;
    this.ValueControl.Properties.DataSource = binding;
    this._ResourceDataSource = binding;
    return 1;
}

完成！为测试效果，在窗体Load事件中造个测试数据，看看效果：

DataTable dataTable = new DataTable("Student"); 
dataTable.Columns.Add("编号", typeof(String));
dataTable.Columns.Add("昵称", typeof(String));
dataTable.Columns.Add("名称", typeof(String)); 
dataTable.Rows.Add(new String[] { "1", "James", "张三" });
dataTable.Rows.Add(new String[] { "2", "Mary", "李四" });
dataTable.Rows.Add(new String[] { "3", "Jack", "王五" });
dataTable.Rows.Add(new String[] { "4", "joy", "赵六" });
dataTable.Rows.Add(new String[] { "5", "jay", "钱七"});
dataTable.Rows.Add(new String[] { "6", "stephen", "康忠鑫"});

kzxSearchCbbeSupperStar.SetSourceTableBinding(dataTable, "名称", "昵称");