如何根据leavetype选择在textbox1中显示emp离开余额

Question

我想根据leavetype和emp id在textbox1中显示emp离开余额。 我正在使用下面的代码，但它没有显示总休假余额。

private void cbleavetype_SelectedIndexChanged()
{
    conn = new SqlConnection(@"Data Source=........")
    conn.Open();
    SqlCommand command = new SqlCommand("select leave from leaveallotment where id='" + comboBox1.Text + "' && leavetype='" + cbleavetype.Text + "'",conn);
    SqlDataAdapter adp = new SqlDataAdapter(command);
    DataTable tbl = new DataTable();
    adp.Fill(tbl);
    // Show total leave in textBox1
    textBox1.Text = cbleavetype.SelectedValue.ToString();
}

Answer 1

我认为需要做的一件事就是改变＆＃39;＆amp;＆amp;＆＃39;到＆＃39;和＆＃39;

Answer 2

您可以使用以下代码段

        connectionString.Open();
        SqlCommand command =
            new SqlCommand(
                "select LeaveCount from leaveallotment  where
                 id= '" + comboBox1.Text + "' and 
                 leavetype='" + comboBox2.Text + "'",
                connectionString);
        SqlDataReader da = command.ExecuteReader();
        if (da.Read()) {
            textBox1.Text = da["LeaveCount"].ToString();
        }
        connectionString.Close();