[Solved] ASP.Net Error: DataBinding: System.Data.DataRowView does not contain a property with the name tCon

Hi Vincenzo67,

You need to specify the columns in your stored procedure instead of *.

Check for null value before selected = true.

Please refer below sample.

HTML

<form id="form1" runat="server">
    <asp:GridView ID="gvProducts" runat="server" AutoGenerateColumns="false" OnRowDataBound="gvProducts_RowDataBound">
        <Columns>
            <asp:BoundField DataField="CIGM" HeaderText="CIGM" ReadOnly="true" />
            <asp:TemplateField
                HeaderText="tCon">
                <ItemTemplate>
                    <asp:DropDownList ID="tCon" runat="server"
                        AutoPostBack="true">
                        <asp:ListItem Text="[ === === === ]" Value=""></asp:ListItem>
                        <asp:ListItem Text="OK" Value="OK"></asp:ListItem>
                        <asp:ListItem Text="KO" Value="KO"></asp:ListItem>
                    </asp:DropDownList>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
</form>

Namespaces

C#

using System.Data;
using System.Configuration;
using System.Data.SqlClient;

VB.Net

Imports System.Data
Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        this.BindGrid();
    }
}
private void BindGrid()
{
    gvProducts.DataSource = RetrieveProducts();
    gvProducts.DataBind();
}


private DataTable RetrieveProducts()
{
    DataTable dt = new DataTable();
    DataSet ds = new DataSet();

    using (SqlConnection myConnectionString = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("Get_tb_g", myConnectionString))
        {
            cmd.CommandTimeout = 2147483;
            cmd.Connection.Open();
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Clear();
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            adapter.Fill(ds);
            if (ds.Tables.Count > 0)
            {
                dt = ds.Tables[0];
            }
        }
    }
    return dt;
}

protected void gvProducts_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList tCon = (DropDownList)e.Row.FindControl("tCon");
        string CIGM = e.Row.Cells[0].Text;
        string sql = "SELECT DISTINCT tCon " + "FROM tb_t " + "WHERE CIGM = '" + CIGM.ToUpper() + "'; ";
        string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(conString))
        {
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        tCon.DataSource = dt;
                        tCon.DataTextField = "tCon";
                        tCon.DataValueField = "tCon";
                        tCon.DataBind();
                        string tCon2 = DataBinder.Eval(e.Row.DataItem, "tCon").ToString();
                        if (tCon.Items.FindByValue(tCon2) != null)
                        {
                            tCon.Items.FindByValue(tCon2).Selected = true;
                        }
                    }
                }
            }
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        Me.BindGrid()
    End If
End Sub

Private Sub BindGrid()
    gvProducts.DataSource = RetrieveProducts()
    gvProducts.DataBind()
End Sub

Private Function RetrieveProducts() As DataTable
    Dim dt As DataTable = New DataTable()
    Dim ds As DataSet = New DataSet()
    Using myConnectionString As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("Get_tb_g", myConnectionString)
            cmd.CommandTimeout = 2147483
            cmd.Connection.Open()
            cmd.CommandType = CommandType.StoredProcedure
            cmd.Parameters.Clear()
            Dim adapter As SqlDataAdapter = New SqlDataAdapter(cmd)
            adapter.Fill(ds)
            If ds.Tables.Count > 0 Then
                dt = ds.Tables(0)
            End If
        End Using
    End Using

    Return dt
End Function

Protected Sub gvProducts_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim tCon As DropDownList = CType(e.Row.FindControl("tCon"), DropDownList)
        Dim CIGM As String = e.Row.Cells(0).Text
        Dim sql As String = "SELECT DISTINCT tCon " & "FROM tb_t " & "WHERE CIGM = '" & CIGM.ToUpper() & "'; "
        Dim conString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As SqlConnection = New SqlConnection(conString)
            Using cmd As SqlCommand = New SqlCommand(sql, con)
                Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                    Using dt As DataTable = New DataTable()
                        sda.Fill(dt)
                        tCon.DataSource = dt
                        tCon.DataTextField = "tCon"
                        tCon.DataValueField = "tCon"
                        tCon.DataBind()
                        Dim tCon2 As String = DataBinder.Eval(e.Row.DataItem, "tCon").ToString()
                        If tCon.Items.FindByValue(tCon2) IsNot Nothing Then
                            tCon.Items.FindByValue(tCon2).Selected = True
                        End If
                    End Using
                End Using
            End Using
        End Using
    End If
End Sub

Screenshot