如何在鼠标悬停时更改DataGridView单元格图像？ [英] How to change DataGridView cell image on mouseover?

问题描述

我正在像这样在datagridviews列单元格中绘制图像：

I am painting an image in a datagridviews columns cells like so:

Private Sub dataGridView1_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles DataGridView1.CellPainting
    If e.ColumnIndex = 20 AndAlso e.RowIndex >= 0 Then

        If String.IsNullOrEmpty(e.Value.ToString) Then

            e.Paint(e.CellBounds, DataGridViewPaintParts.All)
            Dim img As Image = Image.FromFile("C:\Users\me\Desktop\glass.png")
            e.Graphics.DrawImage(img, e.CellBounds.Left + 10, e.CellBounds.Top + 5, 25, 25)
            e.Handled = True
        End If

    End If
End Sub

如果我可以将图像切换到另一个悬停在一个单元格上（仅适用于悬停的单元格，而不是所有单元格）？

Is it possible to switch the image to another if I hover over one of the cells (just for the hovered cell not all cells)?

推荐答案

首先，您的代码正在创建一个每个要显示该图像的单元格的新图像。每个单元实际上并不需要自己的个人图像对象。

First thing, your code is creating a new image for each cell where that image is to be displayed. Each cell doesn't really need its own personal image object.

此外，您可以将映像添加到资源中，而不是从磁盘加载（这意味着可以删除或移动文件）。从那里获取它会 静止 每次创建一个新的图像对象，因此将它们存储在一个数组中：

Also, rather than loading from disk (which means the file could be deleted or moved), you could add the image to resources. Getting it from there will still create a new image object each time, so store them in an array:

Private ImgBalls As Image()

然后像FormLoad这样的私有ImgBalls：

Then somewhere like FormLoad:

' ToDo: add a BulletColor enum for indexing
ImgBalls = New Image() {
                        My.Resources.ballblack, My.Resources.ballblue,
                        My.Resources.ballgreen, My.Resources.ballorange,
                        My.Resources.ballred, My.Resources.ballpurple,
                        My.Resources.ballyellow
                        }

然后使用它 like 悬停（不延迟）：

Then using it like a hover (no delay):

Private Sub dgv1_CellMouseEnter(etc etc etc...
    If e.RowIndex < 0 OrElse dgv1.Rows(e.RowIndex).IsNewRow Then Return

    If e.ColumnIndex = 5 Then
        dgv1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = ImgBalls(6)
    End If
End Sub

Private Sub dgv1_CellMouseLeave(etc etc etc...
    If e.RowIndex < 0 OrElse dgv1.Rows(e.RowIndex).IsNewRow Then Return

    If e.ColumnIndex = 5 Then
        dgv1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = ImgBalls(0)
    End If
End Sub

这会更改默认值当鼠标悬停在上面时，黑色的项目符号会变为黄色：

This changes a default black bullet to yellow when the mouse is over it:

请注意，如果null值无效，而不是图像无效，还可以使用 CellErrorText 提供红色的感叹号和一些文本。

Note that if a null value is invalid, rather than an image you can also use CellErrorText to provide a red exclamation and some text.

这篇关于如何在鼠标悬停时更改DataGridView单元格图像？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！