根据列值使 DataGridView 行具有某种颜色 [英] Making DataGridView rows a certain color based on a column value

问题描述

我正在使用 vb.net 并且我有数据进入我的 DGV，如果它是1"，我有一个标记为已部署的列，我想在已部署的列 RED 中拥有所有带有1"的行，如果它是'0'，我希望所有的行都是绿色的.这是我的方法，现在该列是第 10 列，但它不喜欢 = 运算符.即使我在 1 上使用引号与字符串的等于比较运算符.应该是一个整数，但我想尽一切办法找出它为什么不起作用.

I am using vb.net and I have data coming into my DGV and I have a column labeled deployed if it's a '1', I want to have all the rows with '1' in the deployed column RED and if it's a '0', I want all the rows to be GREEN. This is my method I have, right now the column is the 10th column but it doesn't like the = operator. Even when I use quotes on the 1 with equals compare operator for strings. Should be an integer but I was trying every way I could to see why it's not working.

Private Sub LaptopGrid_CellFormatting(ByVal Sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles LaptopGrid.CellFormatting
    For i As Integer = 0 To LaptopGrid.Rows.Count - 1
        If LaptopGrid.Rows(i).Cells(9).Value = 1 Then
            LaptopGrid.RowsDefaultCellStyle.BackColor = Color.Green
        End If
    Next
End Sub

推荐答案

您的代码有几个问题.

首先，您正在处理 CellFormatting 事件，但您正在迭代每一行以设置背景色.该事件旨在让您对单个特定单元格 执行某些操作，有问题的单元格在事件参数中指示:e.RowIndex 和 e.列索引.使用循环，您可以处理比需要多得多的行，并且一遍又一遍地这样做.

First, you are handling the CellFormatting event but you are iterating every row to set the backcolor. That event is meant for you to do something to a single, specific cell, the one in question is indicated in the event args: e.RowIndex and e.ColumnIndex. Using a loop, you are acting on many more rows than needed and doing so over and over.

其次，VB有数据类型.Int32 是一种类型，String 是另一种类型，而 Object 是另一种类型.在比较之前，您需要将一种类型转换为另一种类型.LaptopGrid.Rows(r).Cells(c).Value 返回 Object(因为一个单元格实际上可以容纳任何东西)，因此与 1 您需要将其转换为整数.

Second, VB has data types. Int32 is one type, String is another, and Object is yet another. You need to convert one type to the other type before you compare. LaptopGrid.Rows(r).Cells(c).Value returns Object (since a cell can literally hold anything), so to compare to 1 you need to convert it to integer.

最后，您可能不需要 CellFormatting 事件.如果有问题的单元格不在屏幕上，则不会触发该事件(可能是用户调整了列的大小).RowPrePaint 另一方面，当行滚动到视图中时会触发.

Finally, you may not want the CellFormatting event for this. If the cell in question is not on screen, the event wont fire (perhaps the user resized the columns). RowPrePaint on the other hand will fire when the row scrolls into view.

Private Sub dgv1_RowPrePaint(sender As Object, 
                   e As DataGridViewRowPrePaintEventArgs) Handles dgv1.RowPrePaint

    ' dont do the NewRow
    If e.RowIndex < 0 OrElse dgv1.Rows(e.RowIndex).IsNewRow Then Return

    ' convert to int32, then compare
    ' act on just this row - e.RowIndex
    If Convert.ToInt32(dgv1.Rows(e.RowIndex).Cells(3).Value) > 3 Then
        dgv1.Rows(e.RowIndex).DefaultCellStyle.BackColor = Color.LemonChiffon
    Else
        dgv1.Rows(e.RowIndex).DefaultCellStyle.BackColor = Color.MistyRose
    End If

End Sub

如果用户可以编辑该单元格值，您将需要相应地更新背景颜色.

If the user can edit that cell value, you will want to update the back color accordingly.

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