Add a line of empty information to the DataTable table so that the first option for DropDownList is empty

Source: Internet
Author: User
Tags first row

Table structure: Description of Column name data type

ID int Child add primary key

userlevel String Department name

Method One: Insert a blank row into the DataTable, and then bind DropDownList to the DataTable

Add a blank line to the first row of a DataTable

DataRow dr = ds. Tables[0]. NewRow ();

dr["name"] = "";

dr["username"] = "";

Ds. Tables[0]. Rows.insertat (DR, 0);

Binding

This.ddlUsername.DataSource = ds. Tables[0]. DefaultView;

This.ddlUsername.DataTextField = "name";

This.ddlUsername.DataValueField = "username";

This.ddlUsername.DataBind ();

Method Two: Bind the DropDownList directly to the DataTable, and then add a blank line to the DataTable.

/***************************************

Binding

This.ddlUsername.DataSource = ds. Tables[0]. DefaultView;

This.ddlUsername.DataTextField = "name";

This.ddlUsername.DataValueField = "username";

This.ddlUsername.DataBind ();

***************************************/

This allows you to dropdownlist the desired value of the binding, and the first line in the DropDownList is blank.

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