之前介绍的使得PDA datagrid 能够进行编辑的实现方法：利用一个隐藏的textbox控件，当用户点击datagrid单元格变化引发事件CurrentCellChanged发生，在该事件中设置textbox可见，且显示信息即为当前选中的单元格的文本，当修改文本信息焦点离开textbox时，将textbox中的内容写入datagrid绑定的datatable中，这样就实现利用一个覆盖在单元格上的可编辑的textbox使得datagrid可编辑的功能。
但是它存在一个问题：当移动DataGrid的滚动条时，textbox仍在原来的位置，没有失去焦点。要解决这个问题，就需要能够捕捉到datagrid的拖动滚动条事件。
查资料后发现，原来Datagrid控件是由三个控件组成，这些控件可以利用DataGrid.controls属性获得，利用DataGrid.controls.count可以获得控件的个数。
那么就可以按照DataGrid.controls[i]用i下标来访问每一个控件。
通过编程测试找到
DataGrid.controls[0]对应的是水平滚动条HScroll
DataGrid.controls[1]对应的是垂直滚动条VScroll
HScrollBar hScrollBar = null;
VScrollBar vScrollBar = null;
//绑定DataGrid滚动事件
private void BindScrollEvent()
{
foreach (Control c in this.Controls)
{
if (c is HScrollBar) hScrollBar = (HScrollBar)c;
if (c is VScrollBar) vScrollBar = (VScrollBar)c;
}
if (hScrollBar != null)
{
hScrollBar.ValueChanged -= new EventHandler(DataGrid_HScrollEvent);
hScrollBar.ValueChanged += new EventHandler(DataGrid_HScrollEvent);
}
if (vScrollBar != null)
{
vScrollBar.ValueChanged -= new EventHandler(DataGrid_VScrollEvent);
vScrollBar.ValueChanged += new EventHandler(DataGrid_VScrollEvent);
}
}
因此我们可以针对水平滚动条，自己编写事件触发过程：
//水平滚动事件
private void DataGrid_HScrollEvent(object sender, EventArgs e)
{
if (txtedit.Focus())
{
txtedit.Visible = false;
}
}
//垂直滚动事件
private void DataGrid_VScrollEvent(object sender, EventArgs e)
{
if (txtedit.Focus())
{
txtedit.Visible = false;
}
}
这样就实现了当点击datagrid的滚动条时让textbox失去焦点。
完整代码
using System;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using System.Collections;
using System.Data;
namespace SmartDeviceProject1
{
public class datagridEx :DataGrid,ISupportInitialize
{
DataGridCell editcell = new DataGridCell();
Rectangle cellpos = new Rectangle();
TextBox txtedit = null;
HScrollBar hScrollBar = null;
VScrollBar vScrollBar = null;
bool isUpdateMode = false;
bool isEditMode = false;
public datagridEx()
{
InitTextBox();
BindScrollEvent();
}
/// <summary>
/// 初始化可编辑TextBox
/// </summary>
private void InitTextBox()
{
txtedit = new TextBox();
this.Controls.Add(txtedit);
txtedit.Visible = false;
txtedit.BringToFront();
txtedit.Text = "grn";
txtedit.KeyPress -= new KeyPressEventHandler(txedit_KeyPress);
txtedit.KeyPress += new KeyPressEventHandler(txedit_KeyPress);
}
//绑定DataGrid滚动事件
private void BindScrollEvent()
{
foreach (Control c in this.Controls)
{
if (c is HScrollBar) hScrollBar = (HScrollBar)c;
if (c is VScrollBar) vScrollBar = (VScrollBar)c;
}
if (hScrollBar != null)
{
hScrollBar.ValueChanged -= new EventHandler(DataGrid_HScrollEvent);
hScrollBar.ValueChanged += new EventHandler(DataGrid_HScrollEvent);
}
if (vScrollBar != null)
{
vScrollBar.ValueChanged -= new EventHandler(DataGrid_VScrollEvent);
vScrollBar.ValueChanged += new EventHandler(DataGrid_VScrollEvent);
}
}
DataGridCell currentcell;
protected override void OnCurrentCellChanged(EventArgs e)
{
if (isUpdateMode)
{
base.OnCurrentCellChanged(e);
return;
}
currentcell = this.CurrentCell;
if (isEditMode && !this.CurrentCell.Equals(editcell))
{
isUpdateMode = true;
this[editcell.RowNumber, editcell.ColumnNumber] = txtedit.Text;
this.CurrentCell = currentcell;
this.Visible = true;
txtedit.Visible = false;
isUpdateMode = false;
isEditMode = false;
}
editcell = this.CurrentCell;
cellpos = this.GetCellBounds(editcell.RowNumber, editcell.ColumnNumber);
txtedit.Left = cellpos.Left - 1;
txtedit.Top = cellpos.Top - 1;
txtedit.Width = cellpos.Width + 2;
txtedit.Height = cellpos.Height + 2;
txtedit.Visible = true;
txtedit.Text = this[editcell.RowNumber, editcell.ColumnNumber].ToString();
txtedit.BringToFront();
txtedit.Focus();
txtedit.SelectAll();
isEditMode = true;
base.OnCurrentCellChanged(e);
}
private void txedit_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Enter)
{
txtedit.Visible = false;
this[currentcell.RowNumber, currentcell.ColumnNumber] = txtedit.Text;
this.Focus();
if (currentcell.RowNumber +1 < this.VisibleRowCount)
currentcell.RowNumber = currentcell.RowNumber + 1;
this.CurrentCell = currentcell;
isUpdateMode = false;
isEditMode = true;
}
}
//水平滚动事件
private void DataGrid_HScrollEvent(object sender, EventArgs e)
{
if (txtedit.Focus())
{
txtedit.Visible = false;
}
}
//垂直滚动事件
private void DataGrid_VScrollEvent(object sender, EventArgs e)
{
if (txtedit.Focus())
{
txtedit.Visible = false;
}
}
#region ISupportInitialize接口实现
public void BeginInit()
{
}
public void EndInit()
{
}
#endregion
}
}
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