c# - 如何为 Dropdownbox C# ASP.NET 获取 Datasource()

Question

我有tblDepartments带列的表DeptID, Department, Description。我也有下拉框drpDepartments。我想Department在下拉框中显示列的内容。我尝试将此 C# 代码用于 winforms，但它不起作用：

        drpDepartments.DataSource = dsDep.Tables["tblDepartment"];
        drpDepartments.DisplayMember = "Department";
        drpDepartments.ValueMember = "DeptID";
        drpDepartments.Text = "Choose Department";

我如何使用 ASP.NET C# 来做到这一点？谢谢。

新代码（仍然无法正常工作）

        sConn = new SqlConnection(sStr);
        daEmp = new SqlDataAdapter("SELECT * FROM tblEmployee", sConn);
        daDep = new SqlDataAdapter("SELECT * FROM tblDepartment", sConn);
        dsEmp = new DataSet();
        dsDep = new DataSet();

        daEmp.Fill(dsEmp, "tblEmployee");
        daDep.Fill(dsDep, "tblDepartment");

        dsEmp.Tables["tblEmployee"].PrimaryKey = new DataColumn[] { dsEmp.Tables["tblEmployee"].Columns["EmployeeID"] };

        DataTable dt=new DataTable();
        daDep.Fill(dt);

        drpDepartments.DataTextField = "Department";
        drpDepartments.DataValueField = "DeptID";
        drpDepartments.DataSource = dt;
        drpDepartments.DataBind();

Answer 1

你必须在 asp.net webForms 中这样称呼它

        drpDepartments.DataSource = dsDep.Tables["tblDepartment"];// Set DataSource Table First
        drpDepartments.DataTextField = "Department";// Set Column Name of DataTable to set as Text Field
        drpDepartments.DataValueField = "DepartmentID";// Set Column Name of DataTable to set as Value Field
        drpDepartments.DataBind();

您必须从using System.Web.UI.WebControls;命名空间使用它。好像您正在使用 winforms 命名空间。

DataTextField等价于DisplayMember和ValueMember等价于DataValueField。

Answer 2

您是否调用了 DataBind()？

drpDepartments.DataSource = dsDep.Tables["tblDepartment"];
drpDepartments.DisplayMember = "Department";
drpDepartments.ValueMember = "DepartmentID";
drpDepartments.Text = "Choose Department";
drpDepartments.DataBind();

Answer 3

drpDepartments.DataSource = ds1;
drpDepartments.DataTextField = "textcol";
drpDepartments.DataValueField = "valuecol";
drpDepartments.DataBind();

在 btn_save 方法中执行此操作后添加此..

 cmd.Parameters.AddWithValue("@a", drpDepartments.SelectedValue);

希望能帮助到你。