How Do I Retrieve the Selected Value from a Data-Bound DropDownList?

DropdownList DataSource - Getting the Selected Value

Question:

How can you access the value selected in a DropDownList bound to a data source?

Answer:

Binding a DropDownList to a data source involves three key elements:

1. DataSource: The source of data, such as a dataset or DataTable.
2. DataValueField: The hidden field that represents the underlying data value.
3. DataTextField: The displayed field that appears in the DropDownList.

Binding the DropDownList:

To bind a DropDownList to a DataTable data source:

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString);

SqlCommand cmd = new SqlCommand("Select * from tblQuiz", con);

SqlDataAdapter da = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();
da.Fill(dt);

DropDownList1.DataTextField = "QUIZ_Name";
DropDownList1.DataValueField = "QUIZ_ID";

DropDownList1.DataSource = dt;
DropDownList1.DataBind();

Getting the Selected Value:

To obtain the selected value after binding:

1. Enable AutoPostBack: Set the AutoPostBack property to "true" in the DropDownList.
2. SelectedIndexChanged Event: Implement the SelectedIndexChanged event to handle the selection.

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    string selectedValue = DropDownList1.SelectedValue;
    string selectedText = DropDownList1.SelectedItem.Text;
}

Using this approach, you can access the selected value and associated text of the DropDownList when the user makes a selection.

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