Question

我需要添加＆＃34;选择＆＃34;在索引0处，不知道DataTable列的计数或名称，因为DataAccessLayer中的此方法将在稍后使用`

// ComboBox Fill Method
public static void ComboBoxFill(ComboBox cbo, string Query, string cboDisplayMember, string cboValueMember)
            {
                con.Open();
                SqlCommand cmd = new SqlCommand(Query, con);
                SqlDataReader dr = cmd.ExecuteReader();
                DataTable dt = new DataTable();
                dt.Load(dr);
                cbo.DataSource = dt;
                cbo.DisplayMember = cboDisplayMember;
                cbo.ValueMember = cboValueMember;
                cbo.SelectedIndex = 0;
                con.Close();
            }

Answer 1

我已通过以下代码解决了这个问题。谢谢大家...

     public static void ComboBoxFill(ComboBox cbo, string Query, string cboDisplayMember, string cboValueMember)
    {
        con.Open();
        SqlCommand cmd = new SqlCommand(Query, con);
        SqlDataReader dr = cmd.ExecuteReader();
        DataTable dt = new DataTable();
        dt.Load(dr);
        DataRow drow = dt.NewRow();
        for (int i = 0; i < dt.Columns.Count ; i++)
        {
            if (dt.Columns[i].ColumnName == cboDisplayMember)
            {
                drow[i] = "Select";
            }
            else if (dt.Columns[i].ColumnName == cboValueMember)
            {
                drow[i] = 0;
            }
            else
            {
                drow[i] = null;
            }
        }

        dt.Rows.InsertAt(drow, 0);

        cbo.DataSource = dt;
        cbo.DisplayMember = cboDisplayMember;
        cbo.ValueMember = cboValueMember;
        cbo.SelectedIndex = 0;
        con.Close();
    }

Answer 2

只需将此行放在ComboBoxFill（）函数中即可。

public static void ComboBoxFill(ComboBox cbo, string Query, string cboDisplayMember, string cboValueMember)
            {
                con.Open();
                SqlCommand cmd = new SqlCommand(Query, con);
                SqlDataReader dr = cmd.ExecuteReader();
                DataTable dt = new DataTable();
                dt.Load(dr);
                cbo.DataSource = dt;

                DataRow newRow = dt.NewRow();
                newRow[0] = "Select";
                dt.Rows.InsertAt(newRow, 0);

                cbo.DisplayMember = cboDisplayMember;
                cbo.ValueMember = cboValueMember;
                cbo.SelectedIndex = 0;
                con.Close();
            }

它将添加＆＃34;选择＆＃34;在位置0

C＃：添加＆＃34;选择＆＃34; item to Dynamic Fill ComboBox方法

2 个答案: