ComponentOne FlexGrid for Winforms提供了丰富的对象模型，是您可以实现强大的功能。C1FlexGrid 用于内置的列过滤，可以通过 AllowFiltering 属性调用。当过滤功能开启时，用户可以通过点击过滤按钮编辑过滤条件。过滤编辑器语序用户根据当前该列展示的数据定制过滤条件，或者定制定制符合当前展示行的过滤条件。
默认的过滤行为是通过下拉列表来展示所有行数值，通过点击下拉列表中的checkbox来显示或隐藏当前值对应的所有行。
在本篇文章中，我们将阐述如何实现Excel 样式的过滤。即为，当前列应用过滤后，过滤下拉列表再次展开时只显示过滤后显示的行数值。
绑定数据
从该连接中您可以了解到如何绑定数据到C1FlexGird：http://helpcentral.componentone.com/nethelp/c1flexgrid/#!Documents/step2of3bindingc1fle.htm 。
定制过滤
定制Grid的过滤行为,我们需要操作过滤编辑器的按钮点击事件。可以通过, 需要捕获用于应用额取消过滤的FilterEditorForm。基本实现逻辑为当过滤应用到当前列时重置当前 C1FlexGrid 的数据源。
private void c1FlexGrid1_MouseDown(object sender, MouseEventArgs e)
{
if (c1FlexGrid1.HitTest(e.X,e.Y).Type == C1.Win.C1FlexGrid.HitTestTypeEnum.FilterIcon)
{
// start the timer if the FilterIcon has been hit
tm.Start();
}
}
void tm_Tick(object sender, EventArgs e)
{
tm.Stop();
foreach (Form f in Application.OpenForms)
{
if (f.Name == "FilterEditorForm" && f.GetType().ToString() == "C1.Win.C1FlexGrid.FilterEditorForm")
{
// Capture the Apply & Clear buttons on the filterdropdown form & assign Handlers to their Click Events
System.Windows.Forms.ToolStripButton clr_btn = ((ToolStripButton)((ToolStrip)f.Controls[0]).Items[1]);
System.Windows.Forms.ToolStripButton app_btn = ((ToolStripButton)((ToolStrip)f.Controls[0]).Items[2]);
clr_btn.Click += new EventHandler(clr_btn_Click);
app_btn.Click += new EventHandler(app_btn_Click);
}
}
}
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点击 Apply 或Clear 按钮时。应用自定义过滤：
// Handling Apply button's Click Event
void app_btn_Click(object sender, EventArgs e)
{
string filter_text = null;
for (int i = 0; i < c1FlexGrid1.Cols.Count; i++)
{
// check for which column the filter is currently active
if (c1FlexGrid1.Cols[ i ].Filter.IsActive == true)
{
object[] filter_values = ((C1.Win.C1FlexGrid.ColumnFilter)(this.c1FlexGrid1.Cols[ i ].Filter)).ValueFilter.ShowValues;
foreach (object value in filter_values)
{
// if the Column is Integer
if (c1FlexGrid1.Cols[ i ].DataType.ToString() == "System.Int32")
{
// check for null values in the column
if (value.ToString() == "")
filter_text += c1FlexGrid1.Cols[ i ].Caption + " Is Null or ";
else
filter_text += c1FlexGrid1.Cols[ i ].Caption + "=" + value + " or ";
}
else // columns with Datatype not as Integer
{
// check for null values in the column
if (value.ToString() == "")
filter_text += c1FlexGrid1.Cols[ i ].Caption + " Is Null or ";
else
filter_text += c1FlexGrid1.Cols[ i ].Caption + " like '" + value + "' or ";
}
}
dv.RowFilter = filter_text.Remove(filter_text.Length - 3); // removing the extra appended or from the filter_text
// Assign the filtered datasource to the Grid
c1FlexGrid1.DataSource = dv;
}
}
}
// Handling Clear button's Click Event
void clr_btn_Click(object sender, EventArgs e)
{
// Assign the default datasource to the Grid
c1FlexGrid1.DataSource = c1NWINDDataSet.Employees;
}
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