如何在下拉列表中添加表字段的2列值

Question

I have a dropdown. I need to bind with two field of datatable value here

ddlitem.datasource= dtitem
ddlitem.datatextfield = dtitem.cloumn["name"].tostring()+"-"+dtitem.cloumn["tagname"].tostring() 

I am doing like this I am getting exception here. How can I combine both the column value in dropdown

and when I retrieve the selected value of the dropdown

I should get only the value of this column value: dtitem.cloumn["name"].tostring()

string stritem=  ddlitem.selecteditem.Text.Tostrigng();

so how can I do the splitting the value of the string?

Answer 1

you need to iterate 1 of the column rows and need to cancatinate your items rather whole column

Edit :

should be like...

for (int count = 0; count < dtitem.Rows.Count; count++)
    {
        dtitem.Rows[count]["name"] = dtitem.Rows[count]["name"].tostring() + "-" + dtitem.Rows[count]["tagname"].tostring();
    }

Answer 2

I assume that dtitem is a DataRow object. I recommend you to create a dictionary object and fill it like

Dictionary<string,string> dicts = new Dictionary<string,string>();

foreach(DataRow row in dt.Rows)
{
  string key = row["name"].ToString();
  string val = String.Format("{0}-{1}",row["name"],row["tagname"]);
}

then bind it to dropdown

dropdown.DataSource = dicts;
dropdown.DataValueField = "Key";
dropdown.DataTextField = "Value";
dropdown.DataBind();

when you get dropdown.SelectedValue , its already the name so you don't need to separate it from tagname

Answer 3

DropDownList.DataTextField will only work with on column/field of the object you're binding to it. If you need to display multiples values, you have some options:

• Edit your query to concatenate the values before the object is passed to your dropdown for binding.
• Create a collection that is derived from your dataobject, which concatenates the values and then bind THAT to your dropdown.
• Add each item to your dropdown programatically, concatenating the values as you go.

Answer 4

Try using the following :

public void Populate_DriverDropDown()
    {
        //Opening and closing connection not required while using SqlDataAdapter 

        //sql command to select the drivers and their ids (displaying both the drivername and firstSurname)
        String sqlQuery = "SELECT driverID, nameDriver+' '+firstSurname AS driverFullname FROM driver ORDER BY driverID ASC";
        //end

        //using SqlDataAdapter and DataSet
       SqlDataAdapter Da = new SqlDataAdapter(sqlQuery, DBConn);

        DataSet Ds = new DataSet();

        Da.Fill(Ds, "driver");

        if (Ds.Tables[0].Rows.Count > 0)
        {
            //populating each dropdown row with driver name and id.
            foreach (DataRow Dr in Ds.Tables[0].Rows)
            {
                VehicleDriver.Items.Add(new ListItem(Dr["driverFullname"].ToString(), Dr["driverID"].ToString()));
            }
        }

        //to have select option at the top of the dropdown list
        VehicleDriver.Items.Insert(0, "Select a driver");

    }

Answer 5

Dictionary<string,string> dicts = new Dictionary<string,string>();

foreach(DataRow row in dt.Rows)
{
  string key = row["name"].ToString();
  string val = String.Format("{0}-{1}",row["name"],row["tagname"]);
}

Please Rewrite this to

Dictionary<string,string> dicts = new Dictionary<string,string>();

foreach(DataRow row in dt.Rows)
{
  string key = row["name"].ToString();
  string val = String.Format("{0}-{1}",row["name"],row["tagname"]);
  dicts.Add(key, val);
}