标签:设计 提示 dex eth 处理 rgs out bind 字符串
背景
需要在gridview中增加一列。之前的数据都是通过Datatable 绑定到GridControl.DataSource呈现。(GridControl 不能只通过非绑定列呈现)
Note that the Grid Control cannot operate with only unbound columns (without binding the control to a data source using the GridControl.DataSource and GridControl.DataMember properties)。
问题描述
在gridview中通道Columns.AddField()添加了一列(GridColumn),当对这一列的单元格进行赋值时无效果。
赋值方式是通过gridView1.SetRowCellValue();
解决方法
响应gridView的CustomUnboundColumnData 消息,其中CustomColumnDataEventArgs 包含以下属性 IsSetData,IsGetData,Value等。
此消息在gridview初始化,以及其它绑定列的数据被修改时被激活,此时IsGetData为true,IsSetData为false;
对非绑定列的单元格进行编辑(添加非绑定列以后默认是可编辑的)和对非绑定列进行SetRowCellValue()时消息也被激活,此时IsSetData为true,IsGetData为false;
在IsSetData为true的时候,改变Value的值对单元格内呈现的值无效,该值不会被显示到界面上。所以SetRowCellValue方法无法对非绑定列的单元格进行赋值。
当IsGetData为true的时候,改变Value的值单元格内的值也就改变了。
通常的,在CustomUnboundColumnData 消息被响应的时候如果IsSetData 为true,该消息会被再次响应,此时IsGetData为true;
所以要使非绑定列的编辑和SetRowCellValue()有效,代码如下:
//以下代码只适用于单行,因为数据只暂存在一个edit对象,当有多行的时候,每一行的数据都有可能变成edit
object edit; private void gridView1_CustomUnboundColumnData(object sender, DevExpress.XtraGrid.Views.Base.CustomColumnDataEventArgs e) { if(e.IsSetData) { edit = e.Value; }else if(e.IsGetData) { e.Value = edit; } }
问题查找过程
当遇到SetRowCellValue()无效的时候,我首先想到的是属性是否设置正确。
首先,非绑定列被创建时,visible 属性为false。由此可见,非绑定列与绑定列相比,有很多属性都是需要手动设置的。
依据以往的了解,决定单元格数据显示的有三个属性:
ColumnType,列的类型
DisplayFormat.FormatType ,格式类型
DisplayFormat.FormatString,格式字符串
后面两个属性在使用绑定列的时候我通常也会设置,所以已经设置好。
于是设置ColumnType,但是该属性为只读类型,看来只适用于绑定列。
通过type关键字提示发现,存在UnboundType,默认情况下该值为None.于是设置为DevExpress.Data.UnboundColumnType.Decimal;
结果依然失败。
Google后发现
需要响应gridView的CustomUnboundColumnData 消息
总结
由于非绑定列在处理数据输入时比较麻烦:消息响应两次,需要新建数据对象进行存储,删除时也需要删除对应数据源。所以不适合作为编辑列。
However, please keep in mind those situations in which unbound columns retrieve their data from a custom data source, and a record is added to or deleted from the grid‘s main data source. When a record is added, you usually need to add a new entry to the custom data source that corresponds to the new record in the grid. Similarly, when a record is deleted you usually need to delete the corresponding entry in the custom data source. To receive notifications about a record that has been added or removed, use the methods provided by the data source.
猜测
官方设计的非绑定列运用场景主要适用以下示例场景:
官方示例代码:
using DevExpress.XtraGrid.Views.Base; using DevExpress.XtraGrid.Views.Grid; using DevExpress.XtraGrid.Columns; private void Form1_Load(object sender, System.EventArgs e) { // ... gridControl1.ForceInitialize(); // Create an unbound column. GridColumn unbColumn = gridView1.Columns.AddField("Total"); unbColumn.VisibleIndex = gridView1.Columns.Count; unbColumn.UnboundType = DevExpress.Data.UnboundColumnType.Decimal; // Disable editing. unbColumn.OptionsColumn.AllowEdit = false; // Specify format settings. unbColumn.DisplayFormat.FormatType = DevExpress.Utils.FormatType.Numeric; unbColumn.DisplayFormat.FormatString = "c"; // Customize the appearance settings. unbColumn.AppearanceCell.BackColor = Color.LemonChiffon; } // Returns the total amount for a specific row. decimal getTotalValue(GridView view, int listSourceRowIndex) { decimal unitPrice = Convert.ToDecimal(view.GetListSourceRowCellValue(listSourceRowIndex, "UnitPrice")); decimal quantity = Convert.ToDecimal(view.GetListSourceRowCellValue(listSourceRowIndex, "Quantity")); decimal discount = Convert.ToDecimal(view.GetListSourceRowCellValue(listSourceRowIndex, "Discount")); return unitPrice * quantity * (1 - discount); } // Provides data for the Total column. private void gridView1_CustomUnboundColumnData(object sender, CustomColumnDataEventArgs e) { GridView view = sender as GridView; if (e.Column.FieldName == "Total" && e.IsGetData) e.Value = getTotalValue(view, e.ListSourceRowIndex); }
参考资料:
官方文档:
https://documentation.devexpress.com/#WindowsForms/CustomDocument1477
同一问题:
https://stackoverflow.com/questions/20137808/how-to-set-a-value-to-unbound-column-cell-setrowcellvalue-grinview-winforms
C# winform dev gridcontrol 非绑定列(unbound)的使用
标签:设计 提示 dex eth 处理 rgs out bind 字符串
原文地址:http://www.cnblogs.com/lianshanIn17/p/6955310.html