DataGridView之行的展开与收缩
很多数据都有父节点与子节点,我们希望单击父节点的时候可以展开父节点下的子节点数据。
比如一个医院科室表,有父科室与子科室,点击父科室后,在父科室下面可以展现该科室下的所有子科室。
我们来说一下在DataGridView中如何实现这个功能。
首先,创建示例数据:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
其实思路很简单,就是在展开父节点的时候,在父节点下插入新的DataGridViewRow;收缩父节点的时候,在父节点下删除该子节点的DataGridViewRow。
为了简便,代码中的数据读取我都直接硬编码了。
加载父节点数据,除了数据库中的列外我还新加了两列:IsEx与EX。
private void DataGridBing(DataTable table) { if (table.Rows.Count > 0) { for (int i = 0; i < table.Rows.Count; i++) { int k = this.dataGridView1.Rows.Add(); DataGridViewRow row = this.dataGridView1.Rows[k]; row.Cells["ID"].Value = table.Rows[i]["ID"]; row.Cells["DName"].Value = table.Rows[i]["DName"]; row.Cells["Daddress"].Value = table.Rows[i]["Daddress"]; row.Cells["Dtelphone"].Value = table.Rows[i]["Dtelphone"]; //用于显示该行是否已经展开 row.Cells["IsEx"].Value = "false"; //用于显示展开或收缩符号,为了简单我就直接用字符串了,其实用图片比较美观 row.Cells["EX"].Value = "+"; } } }
下面就是Cell的单击事件了,分别在事件中写展开的插入与收缩的删除.
插入子节点:
string isEx=this.dataGridView1.Rows[e.RowIndex].Cells["IsEx"].Value.ToString(); if (this.dataGridView1.Columns[e.ColumnIndex].Name == "EX" && isEx=="false") { string id = this.dataGridView1.Rows[e.RowIndex].Cells["ID"].Value.ToString(); DataTable table = GetDataTable("select * from Department where DparentId="+id); if (table.Rows.Count > 0) { //插入行 this.dataGridView1.Rows.Insert(e.RowIndex+1, table.Rows.Count); for (int i = 0; i < table.Rows.Count; i++) { DataGridViewRow row = this.dataGridView1.Rows[e.RowIndex + i+1]; row.DefaultCellStyle.BackColor = Color.CadetBlue; row.Cells["ID"].Value = table.Rows[i]["ID"]; row.Cells["DName"].Value = table.Rows[i]["DName"]; row.Cells["Daddress"].Value = table.Rows[i]["Daddress"]; row.Cells["Dtelphone"].Value = table.Rows[i]["Dtelphone"]; } } //将IsEx设置为true,标明该节点已经展开 this.dataGridView1.Rows[e.RowIndex].Cells["IsEx"].Value = "true"; this.dataGridView1.Rows[e.RowIndex].Cells["EX"].Value = "-";
删除子节点:
if (this.dataGridView1.Columns[e.ColumnIndex].Name == "EX" && isEx == "true") { string id = this.dataGridView1.Rows[e.RowIndex].Cells["ID"].Value.ToString(); DataTable table = GetDataTable("select * from Department where DparentId=" + id); if (table.Rows.Count > 0) { //利用Remove for (int i = 0; i < table.Rows.Count; i++) { foreach (DataGridViewRow row in this.dataGridView1.Rows) { if (row.Cells["ID"].Value.Equals(table.Rows[i]["ID"])) { this.dataGridView1.Rows.Remove(row); } } } } ////将IsEx设置为false,标明该节点已经收缩 this.dataGridView1.Rows[e.RowIndex].Cells["IsEx"].Value = "false"; this.dataGridView1.Rows[e.RowIndex].Cells["EX"].Value = "+"; }
这里面通过比较ID来唯一确定一行,循环比较多,因为子节点是紧接着父节点的,我们可以确定子节点所在的行数,所以用RemoveAt()方法更好。
//利用RemoveAt for (int i = table.Rows.Count; i > 0; i--) { //删除行 this.dataGridView1.Rows.RemoveAt(i + e.RowIndex); }
上面的做法是通过不断的插入与删除来实现,但这样与数据库的交互变得很频繁。更好的做法应该是插入一次,然后通过隐藏或显示行来实现我们的效果。
为此,我们还要在grid中新增两个列:
IsInsert:用来判断该行是否已经有插入子节点数据
RowCount:用来保存该行下插入的子节点数量。
在方法DataGridBing中,绑定数据时,应该再加一列:
//是否插入 row.Cells["IsInsert"].Value = "false";
而在增加节点的时候,我们要多做一个判断,如果IsInsert为false就插入数据,如果为true就显示数据
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
if (this.dataGridView1.Columns[e.ColumnIndex].Name == "EX" && isEx=="false") { if (this.dataGridView1.Rows[e.RowIndex].Cells["IsInsert"].Value.ToString() == "false") { string id = this.dataGridView1.Rows[e.RowIndex].Cells["ID"].Value.ToString(); DataTable table = GetDataTable("select * from Department where DparentId=" + id); if (table.Rows.Count > 0) { //插入行 this.dataGridView1.Rows.Insert(e.RowIndex + 1, table.Rows.Count); for (int i = 0; i < table.Rows.Count; i++) { DataGridViewRow row = this.dataGridView1.Rows[e.RowIndex + i + 1]; row.DefaultCellStyle.BackColor = Color.CadetBlue; row.Cells["ID"].Value = table.Rows[i]["ID"]; row.Cells["DName"].Value = table.Rows[i]["DName"]; row.Cells["Daddress"].Value = table.Rows[i]["Daddress"]; row.Cells["Dtelphone"].Value = table.Rows[i]["Dtelphone"]; } this.dataGridView1.Rows[e.RowIndex].Cells["IsInsert"].Value = "true"; this.dataGridView1.Rows[e.RowIndex].Cells["RowCount"].Value = table.Rows.Count; } } else { //显示数据 int RowCount = Convert.ToInt32(this.dataGridView1.Rows[e.RowIndex].Cells["RowCount"].Value); for (int i = 1; i <= RowCount; i++) { this.dataGridView1.Rows[e.RowIndex + i].Visible = true; } } //将IsEx设置为true,标明该节点已经展开 this.dataGridView1.Rows[e.RowIndex].Cells["IsEx"].Value = "true"; this.dataGridView1.Rows[e.RowIndex].Cells["EX"].Value = "-"; }
收缩的时候,我们直接隐藏行就可以了.
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
if (this.dataGridView1.Columns[e.ColumnIndex].Name == "EX" && isEx == "true") { int RowCount = Convert.ToInt32(this.dataGridView1.Rows[e.RowIndex].Cells["RowCount"].Value); for (int i = 1; i <= RowCount; i++) { //隐藏行 this.dataGridView1.Rows[e.RowIndex + i].Visible = false; } ////将IsEx设置为false,标明该节点已经收缩 this.dataGridView1.Rows[e.RowIndex].Cells["IsEx"].Value = "false"; this.dataGridView1.Rows[e.RowIndex].Cells["EX"].Value = "+"; }