public DataGridViewTextBoxEditingControl CellEdit = null;

int idx = 1;
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
if (this.dataGridView1.CurrentCellAddress.X == idx)
{
CellEdit = (DataGridViewTextBoxEditingControl)e.Control;
CellEdit.SelectAll();
CellEdit.KeyPress += Cells_KeyPress; //绑定事件
}
}

private void Cells_KeyPress(object sender, KeyPressEventArgs e) //自定义事件
{
if (this.dataGridView1.CurrentCellAddress.X == idx)
{
if (e.KeyChar == 46)
{
e.Handled = false;
return;
}
if (!(e.KeyChar >= ‘0‘ && e.KeyChar <= ‘9‘)) e.Handled = true;
if (e.KeyChar == ‘\b‘) e.Handled = false;
}
}

private void dataGridView1_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
{

if (dataGridView1.Rows[e.RowIndex].IsNewRow) return;
decimal dci;
if (e.ColumnIndex == idx)
{
if (e.FormattedValue != null && e.FormattedValue.ToString().Length > 0)
{
if (!decimal.TryParse(e.FormattedValue.ToString(), out dci) || dci < 0)
{
e.Cancel = true;
MessageBox.Show("请输入数字或小数", "提示",
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}
}

DataGridView 设置某个列为只能为数字