Question

我正在绑定一个DropDownList，我在第一列中有FirstName而在第二列中有LastName作为DDL

protected void GridView1_RowDataBound1(object sender, GridViewRowEventArgs e)
{ 
    DataTable myTable = new DataTable();
    DataColumn productIDColumn = new DataColumn("FirstName");
    DataColumn productNameColumn = new DataColumn("LastName");

    myTable.Columns.Add(productNameColumn);
    DataSet ds = new DataSet();

    ds = get();
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        var categoryID = (e.Row.Cells[0].Text);
        var expression = "FirstName "+categoryID;

        DropDownList ddl = (DropDownList)e.Row.FindControl("DropDownList1");

        DataRow[] rows = ds.Tables[0].Select(expression);
        foreach (DataRow row in rows)
        {
            DataRow newRow = myTable.NewRow();
            newRow["UserId"] = row["UserId"];
            newRow["LastName"] = row["LastName"];
            myTable.Rows.Add(newRow);
        }

        ddl.DataSource = myTable;
        ddl.DataTextField = "LastName";
        ddl.DataValueField = "UserId";
        ddl.DataBind();
    }
}

我在DataRow [] rows = ds.Tables [0]收到类似Filter expression 'FirstName ' does not evaluate to a Boolean term的错误.Select（expression）;

任何人都可以帮我解决这个问题吗？

Answer 1

你的表达没有任何意义。我期待的是：

var expression = "FirstName = 'John'";

或

var expression = "CategoryId = 42";

查看Select方法的文档：http://msdn.microsoft.com/en-us/library/det4aw50.aspx

Answer 2

您需要比较表达式中的2个值。阅读这篇文章：C# DataTable Select

过滤器表达式'FirstName'不会计算为布尔项

2 个答案: