DataGridViewで特定のセルの色を変更する方法

DataGridViewで特定のセルの色を変更する方法
VB.NET

Private Sub dgv1_CellMouseEnter(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dgv1.CellMouseEnter
    If e.ColumnIndex >= 0 And e.RowIndex >= 0 Then
        Dim dgv As DataGridView = CType(sender, DataGridView)
        dgv(e.ColumnIndex, e.RowIndex).Style.BackColor = Color.Red
        dgv(e.ColumnIndex, e.RowIndex).Style.SelectionBackColor = Color.Red
    End If
End Sub

Private Sub dgv1_CellMouseLeave(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dgv1.CellMouseLeave
    If e.ColumnIndex >= 0 And e.RowIndex >= 0 Then
        Dim dgv As DataGridView = CType(sender, DataGridView)
        dgv(e.ColumnIndex, e.RowIndex).Style.BackColor = Color.Empty
        dgv(e.ColumnIndex, e.RowIndex).Style.SelectionBackColor = Color.Empty
    End If
End Sub

C#

private void dgv1_CellMouseEnter(object sender,
    DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex >= 0 && e.RowIndex >= 0)
    {
        DataGridView dgv = (DataGridView)sender;
        dgv[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.Red;
        dgv[e.ColumnIndex, e.RowIndex].Style.SelectionBackColor = Color.Red;
    }
}

private void dgv1_CellMouseLeave(object sender,
    DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex >= 0 && e.RowIndex >= 0)
    {
        DataGridView dgv = (DataGridView)sender;
        dgv[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.Empty;
        dgv[e.ColumnIndex, e.RowIndex].Style.SelectionBackColor = Color.Empty;
    }
}

DataGridViewCellStyleを複数セルに適用する方法
VB.NET

Private defaultCellStyle As DataGridViewCellStyle
Private mouseCellStyle As DataGridViewCellStyle

Private Sub Form1_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
    Me.defaultCellStyle = New DataGridViewCellStyle()
    Me.mouseCellStyle = New DataGridViewCellStyle()
    Me.mouseCellStyle.BackColor = Color.Red
    Me.mouseCellStyle.SelectionBackColor = Color.Red
End Sub

Private Sub dgv1_CellMouseEnter(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dgv1.CellMouseEnter
    If e.ColumnIndex >= 0 And e.RowIndex >= 0 Then
        Dim dgv As DataGridView = CType(sender, DataGridView)
        dgv(e.ColumnIndex, e.RowIndex).Style = Me.mouseCellStyle
    End If
End Sub

Private Sub dgv1_CellMouseLeave(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dgv1.CellMouseLeave
    If e.ColumnIndex >= 0 And e.RowIndex >= 0 Then
        Dim dgv As DataGridView = CType(sender, DataGridView)
        dgv(e.ColumnIndex, e.RowIndex).Style = Me.defaultCellStyle
    End If
End Sub

C#

private DataGridViewCellStyle defaultCellStyle;
private DataGridViewCellStyle mouseCellStyle;

private void Form1_Load(object sender, EventArgs e)
{
    this.defaultCellStyle = new DataGridViewCellStyle();
    this.mouseCellStyle = new DataGridViewCellStyle();
    this.mouseCellStyle.BackColor = Color.Red;
    this.mouseCellStyle.SelectionBackColor = Color.Red;
}

private void dgv1_CellEnter(object sender,
    DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex >= 0 && e.RowIndex >= 0)
    {
        DataGridView dgv = (DataGridView)sender;
        dgv[e.ColumnIndex, e.RowIndex].Style = this.mouseCellStyle;
    }
}

private void dgv1_CellLeave(object sender,
    DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex >= 0 && e.RowIndex >= 0)
    {
        DataGridView dgv = (DataGridView)sender;
        dgv[e.ColumnIndex, e.RowIndex].Style = this.defaultCellStyle;
    }
}

ヘッダーのセル色を変更する方法
VB.NET

dgv1.ColumnHeadersDefaultCellStyle.BackColor = Color.Yellow
dgv1.RowHeadersDefaultCellStyle.BackColor = Color.Red
dgv1.TopLeftHeaderCell.Style.BackColor = Color.Blue

C#

dgv1.ColumnHeadersDefaultCellStyle.BackColor = Color.Yellow;
dgv1.RowHeadersDefaultCellStyle.BackColor = Color.Red;
dgv1.TopLeftHeaderCell.Style.BackColor = Color.Blue;