Is there a way to add a blank Item on data binded Combox?

Is there a way to add a blank Item on data binded Combox?

• pallavi19321

  Hi,

  The code posted above this post is for web application

  For windows forms try this: comboBox1.Items.Add("");

  hth,

  Michael Castillones

  
  
  

• mlamb

  What i did is, when i add a new row i specify the value for my keyfiled as zero.

  something like this.

  dsDataSet.Clear();
  theAdapter.Fill(dsDataSet, "Table");
  tblTable = dsDataSet.Tables("Table");
  myRow = tblTable.NewRow;

  myRow("DisplayField") = "";

  //------------------------
  myRow("KeyField") = 0; // ------> keyfield as ZERO
  //--------------------------

  tblTable.Rows.InsertAt(myRow, 0);
  objCombo.DataSource = null;
  objCombo.Items.Clear();
  objCombo.DataSource = tblTable;
  objCombo.DisplayMember = "DisplayField";
  objCombo.ValueMember = "KeyField";
  

  
  

• Inuya5ha

  what I mean is the combox is binded to a Datatable or Arraylist something like this

  ComboBox1.DataSource = DataTable or ArrayList

  ComboBox1.ValueMember = "ID"

  ComboBox1.DisplayMember ="ValueName"

  IF I used the Item.ADD("") theres gonna be an error. I have a solution with this but i dont like the concept. what I did is before I set the combox datasource I add a Blank row on Datatable or Arraylist. Is there any other way to do this by not adding a blank row .

  
  

• Jesse Cheng

  You can put this in the Page_Load:

  yourComboBox.Items.Insert(0, New ListItem(" "))

  This will create a blank space in your Combobox.

  
  

• Jay G

  Hi,
  I did the same thing and it worked absolutely fine but there is one problem.
  After I bind the combobox the way you discribed,
  If i do following
  cbo.selectedvalue= <value of the first item after blank item>
  it is throwing an exception.
  ------------
  In Method: Void set_SelectedIndex(Int32)
  
  Specified argument was out of the range of valid values.
  Parameter name: '-2147483648' is not a valid value for 'index'.
  -----------
  
  Any idea why is this happening
  
  here using selected value i am selecting the first item after the blank item.
  
  
  Thanks
  Lav
  
  

• Johan Cyprich

  Hi Teo,

  You cannot add a blank item on combobox once's it is binded to a datasource. Iterate your code using Datatable datasource. First you do your adding of blank item to datatable then bind it as datasource.

  Here is a code example:

  DataSet dsDataSet = new DataSet();
  DataTable tblTable;
  DataRow myRow;
  SqlConnection myConn;
  myConn = new SqlConnection();
  myConn.ConnectionString = gsConnStr;
  myConn.Open();
  theAdapter = new SqlDataAdapter(pSQL, myConn);
  dsDataSet.Clear();
  theAdapter.Fill(dsDataSet, "Table");
  tblTable = dsDataSet.Tables("Table");
  myRow = tblTable.NewRow;
  myRow("DisplayField") = "";
  tblTable.Rows.InsertAt(myRow, 0);
  objCombo.DataSource = null;
  objCombo.Items.Clear();
  objCombo.DataSource = tblTable;
  objCombo.DisplayMember = "DisplayField";
  objCombo.ValueMember = "KeyField";
  objCombo.SelectedValue = 0;
  dsDataSet = null;
  tblTable = null;
  myConn.Close();

  Hope It Helps,

  
  Michael Castillones, MCP

  
  
  
• Is there a way to add a blank Item on data binded Combox?