Question

当我尝试数据dropdownlist时，得到了这个：system.data.datarowview
我错了什么？

 string strQuery = "Select Item FROM Calendar Where UserD="Test";
 SqlConnection myConn;
 SqlDataAdapter sqlDa = new SqlDataAdapter(strQuery,myConn);
 DataTable sqlTa = new DataTable("Test");
 da.Fill(sqlTa);
 ddlList.DataSource = sqlTa;
 ddlList.DataBind();

Answer 1

string strQuery = "Select Item FROM Calendar Where UserD='Test'";

请注意，您需要在字符串周围使用单引号，因为在代码中您没有完成初始字符串，因此其余代码只是strQuery的一部分。

此外如果您将来带回多个字段，当您绑定下拉列表时，您需要指定数据库中的哪个字段是值，哪个是显示的文本。< / p>

ddlList.DataSource = sqlTa;
ddlList.DataValueField = "ValueFieldFromDatabaseResults";
ddlList.DataTextField = "ShownTextFieldFromDatabaseResults";
ddlList.DataBind();

Answer 2

您需要告诉它使用哪些字段作为值和文本。

ddlList.DataSource = sqlTa;
ddlList.DataValueField = "ValueField";
ddlList.DataTextField = "TextField";
ddlList.DataBind();

你的select语句缺少一个“。应该是：

"Select Item FROM Calendar Where UserD='Test'"

示例是：

正如瑞安指出的那样，如果你要撤回一个领域，那么你可以这样做：

        DataTable dtTable = new DataTable();

        try
        {
            using (SqlConnection sqlConnection = new SqlConnection("Your connection"))
            {
                using (SqlCommand sqlCommand = new SqlCommand("Select Item FROM Calendar Where UserD='Test'", sqlConnection))
                {
                    sqlConnection.Open();

                    using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                    {
                        dtTable.Load(sqlDataReader);
                        sqlDataReader.Close();
                    }
                }
            }
        }
        catch (Exception error)
        {
            throw error;
        }

        ddlList.DataSource = dtTable;
        ddlList.DataBind();

但如果你有一个以上的字段，那么你可以这样做：

        DataTable dtTable = new DataTable();

        try
        {
            using (SqlConnection sqlConnection = new SqlConnection("Your connection"))
            {
                using (SqlCommand sqlCommand = new SqlCommand("Select Item, id FROM Calendar Where UserD='Test'", sqlConnection))
                {
                    sqlConnection.Open();

                    using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                    {
                        dtTable.Load(sqlDataReader);
                        sqlDataReader.Close();
                    }
                }
            }
        }
        catch (Exception error)
        {
            throw error;
        }

        ddlList.DataSource = dtTable;
        ddlList.DataValueField = "id";
        ddlList.DataTextField = "item";
        ddlList.DataBind();

Answer 3

添加此行

ddlList.DataSource = sqlTa;
ddlList.DataValueField = "ValueFieldFromDatabaseResults";
ddlList.DataTextField = "ShownTextFieldFromDatabaseResults";
ddlList.DataBind();

然后你错过了

的连接字符串

SqlConnection myConn="must add your connection string code here "

您尚未打开连接字符串

添加myconn.open()

的

 SqlConnection myConn="must add your connection string code here "
`myconn.open()`
 SqlDataAdapter sqlDa = new SqlDataAdapter(strQuery,myConn)

Answer 4

试试这个..

 ddlList.DataSource = sqlTa;                 
 ddlList.DataTextField = "class";
 ddlList.DataBind();

添加ddList.Value="somefield"是可选的

数据绑定下拉列表

4 个答案: