C# DataGridView columns 1 与 columns 1 比较像这个图像

Question

我要比较：

if(already employee id == last cell employee)
{
    MessagBox.show(Your Value is duplicated)
}

As shown in image

Answer 1

这一点为您指明了正确的方向：

private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
{
    // Data of inserted value
    var rowIndex = e.RowIndex;
    var colIndex = e.ColumnIndex;
    var insertedValue = (dataGridView1[colIndex, rowIndex].Value ?? "").ToString();

    foreach(DataGridViewRow row in dataGridView1.Rows)
    {
        // If current cell == insertedValue but not the same row
        if((row.Cells["ColumnID"].Value ?? "").ToString() == insertedValue && row.Index != rowIndex)
        {
            MessageBox.Show("Your Value is duplicated");
        }
    }
}

Linq也是可以的：

private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
{
    var insertedValue = (dataGridView1[e.ColumnIndex, e.RowIndex].Value ?? "").ToString();

    dataGridView1.Rows.Cast<DataGridViewRow>()
        .Where
        (   
            x => (x.Cells["ColumnID"].Value ?? "").ToString() == insertedValue
            && x.Index != e.RowIndex
        )
        .ToList()
        .ForEach(x => MessageBox.Show("Your Value is duplicated"));
}

注意这个不会删除插入的值。因此，如果您再次插入相同的值，MessageBox 将增加 2 倍。