locked
ExecuteScalar error getting data from databases to label text RRS feed

  • Question

  • User-1998474842 posted

    Dear all i have a ExecuteScalar error could you help me guys ?

    Compilation Error 
      Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 
    
     Compiler Error Message: CS1061: 'string' does not contain a definition for 'ExecuteScalar ' and no extension method 'ExecuteScalar' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?)
    
    Source Error:
    
    
     
    
    Line 37:         conn.Open();
    Line 38: 
    Line 39:         lbltotalRecipe.Text = connString.ExecuteScalar();
    Line 40:         conn.Close();
    Line 41: 
    
     
    

    <asp:Label cssClass="content2" runat="server" id="lbltotalRecipe" />
    using System;
    using System.Configuration;
    using System.Data;
    using System.Data.OleDb;
    
    
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            
        //Call TotalRecipeCount Sub routine - get the number recipes
            TotalRecipeCount();
    
    
        }
    
        //Get the total number of recipes
    
        public void TotalRecipeCount()
        {
    
    
            // Get connection string from web.config file
            string connString = ConfigurationManager.ConnectionStrings["AccessPMNDB"].ConnectionString;
            // Create SqlConnection object
            OleDbConnection conn = new OleDbConnection(connString);
            conn.ConnectionString = connString;
            // SQL query to retrieve data from database
            string sqlQuery = "Select Count(ID) From Recipes";
            // Create SqlCommand object
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = sqlQuery;
            // open connection and then binding data into RepeaterRSS control
            conn.Open();
    
            lbltotalRecipe.Text = connString.ExecuteScalar();
            conn.Close();
    
    
        }
    
    
    }

    Thursday, July 21, 2016 11:29 PM

Answers

  • User283571144 posted

    Hi peshangm,

    I suggest you replace lbltotalRecipe.Text = cmd.ExecuteScalar(); with lbltotalRecipe.Text = cmd.ExecuteScalar().ToString();

    And test it again.

    Best Regards,

    Brando 

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, July 22, 2016 12:14 PM
  • User753101303 posted

    Hi,

    No this is another error. The first one is because you tried to call ExecuteScalar against a string rather than against a connection. command.

    This one is because ExecuteScalar returns an object that you then assign to a string (if accepted and the object returned is not a string it would fail anyway at runtime and C# requires to you explicitely mention that you do expect this object to string conversion).

    So you have to use lbltotalRecipe.Text = (string)cmd.ExecuteScalar();

    Using ToString() as suggested earlier will work as well but the solution above would be the same if your query returns an integer or any other type (just replace of course (string) with the appropriate type).

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, July 22, 2016 12:40 PM

All replies

  • User283571144 posted

    Hi peshangm,

    peshangm

    Compilation Error Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. Compiler Error Message: CS1061: 'string' does not contain a definition for 'ExecuteScalar ' and no extension method 'ExecuteScalar' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?) Source Error: Line 37: conn.Open(); Line 38: Line 39: lbltotalRecipe.Text = connString.ExecuteScalar(); Line 40: conn.Close(); Line 41:

    As far as I know, This error means you use a "string" object to use sqlcommand's ExecuteScalar method.


    I suggest you could replace "lbltotalRecipe.Text = connString.ExecuteScalar();" with "lbltotalRecipe.Text = cmd.ExecuteScalar();".


    It will work well.


    More details about "SqlCommand.ExecuteScalar Method", you could refer to follow link:
    https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar(v=vs.110).aspx


    Best Regards,
    Brando

    Friday, July 22, 2016 2:47 AM
  • User-1998474842 posted

    i changed but the same error

    using System;
    using System.Configuration;
    using System.Data;
    using System.Data.OleDb;
    
    
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            
        //Call TotalRecipeCount Sub routine - get the number recipes
            TotalRecipeCount();
    
    
        }
    
        //Get the total number of recipes
    
        public void TotalRecipeCount()
        {
    
    
            // Get connection string from web.config file
            string connString = ConfigurationManager.ConnectionStrings["AccessPMNDB"].ConnectionString;
            // Create SqlConnection object
            OleDbConnection conn = new OleDbConnection(connString);
            conn.ConnectionString = connString;
            // SQL query to retrieve data from database
            string sqlQuery = "Select Count(ID) From Recipes";
            // Create SqlCommand object
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = sqlQuery;
            // open connection and then binding data into RepeaterRSS control
            conn.Open();
    
            lbltotalRecipe.Text = cmd.ExecuteScalar();
            conn.Close();
    
    
        }
    
    
    }
    Compilation Error 
      Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 
    
     Compiler Error Message: CS0266: Cannot implicitly convert type 'object' to 'string'. An explicit conversion exists (are you missing a cast?)
    
    Source Error:
    
    
     
    
    Line 37:         conn.Open();
    Line 38: 
    Line 39:         lbltotalRecipe.Text = cmd.ExecuteScalar();
    Line 40:         conn.Close();
    Line 41: 
    
     
    



    Friday, July 22, 2016 11:01 AM
  • User283571144 posted

    Hi peshangm,

    I suggest you replace lbltotalRecipe.Text = cmd.ExecuteScalar(); with lbltotalRecipe.Text = cmd.ExecuteScalar().ToString();

    And test it again.

    Best Regards,

    Brando 

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, July 22, 2016 12:14 PM
  • User753101303 posted

    Hi,

    No this is another error. The first one is because you tried to call ExecuteScalar against a string rather than against a connection. command.

    This one is because ExecuteScalar returns an object that you then assign to a string (if accepted and the object returned is not a string it would fail anyway at runtime and C# requires to you explicitely mention that you do expect this object to string conversion).

    So you have to use lbltotalRecipe.Text = (string)cmd.ExecuteScalar();

    Using ToString() as suggested earlier will work as well but the solution above would be the same if your query returns an integer or any other type (just replace of course (string) with the appropriate type).

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Friday, July 22, 2016 12:40 PM