在VS2010中对项目运行代码分析

Question

I am running the code Analysis on my project. I am getting 8 warnings and 0 errors. I am not sure what they mean but I have 6 that are the same code (CA2000) and the other 2 are the same code (CA2240). Is this a common warning?

Warning 1 CA2000 : Microsoft.Reliability : In method 'AdminDisplay.AdminDropDown_SelectedIndexChanged(object, EventArgs)', call System.IDisposable.Dispose on object 'ad' before all references to it are out of scope. 

Warning 2 CA2000 : Microsoft.Reliability : In method 'AdminDisplay.AdminDropDown_SelectedIndexChanged(object, EventArgs)', call System.IDisposable.Dispose on object 'cmd' before all references to it are out of scope. 

Warning 3 CA2000 : Microsoft.Reliability : In method 'AdminDisplay.AdminDropDown_SelectedIndexChanged(object, EventArgs)', call System.IDisposable.Dispose on object 'conn' before all references to it are out of scope. 

Warning 5 CA2240 : Microsoft.Usage : Add an implementation of GetObjectData to type 'FoundationDataSet'.

Warning 7 CA2000 : Microsoft.Reliability : In method 'WebForm1.ExecuteInsert(string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string, string)', object 'conn' is not disposed along all exception paths.

I have the "using" but I am still getting that warning. Is my syntax incorrect?

using (SqlConnection conn = new SqlConnection("Data Source=xx.xx.x.xx;Initial Catalog=tablenamae;User ID=xxx;Password=xxxxxxx"))
{
    DataTable dt = new DataTable();

    conn.Open();

    SqlCommand cmd = new SqlCommand("GetStudentInfo", conn);

    cmd.CommandType =CommandType.StoredProcedure;

    cmd.Parameters.Add(new SqlParameter("@ID", AdminDropDown.SelectedValue));

    //cmd.Connection.Open();
    //cmd.ExecuteNonQuery();

    SqlDataAdapter ad = new SqlDataAdapter(cmd);

    ad.Fill(dt);     

    if (dt.Rows.Count > 0)
    {
        //If you want to get mutiple data from the database then you need to write a simple looping
        txtFirstName.Text = dt.Rows[0]["FirstName"].ToString();

        txtMiddleName.Text = dt.Rows[0]["MiddleName"].ToString();

        txtLastName.Text = dt.Rows[0]["LastName"].ToString();

        txtSignature.Text = dt.Rows[0]["Signature"].ToString();

    }

    cmd.Connection.Close();
}  

Any ideas on how to fix these errors? Thanks

Answer 1

Just add eg ad.Dispose() to your code. The warning is not about the syntax but it is about a missing call to Dispoable objects (and that can lead into memory leaks and other problems). If an objects implements IDisposable you can put it into a using block. The relation to garbage collection is demystified here .

using (SqlConnection conn = new SqlConnection("Data Source=xx.xx.x.xx;Initial Catalog=tablenamae;User ID=xxx;Password=xxxxxxx"))
{
    DataTable dt = new DataTable();

    conn.Open();

    SqlCommand cmd = new SqlCommand("GetStudentInfo", conn);

    cmd.CommandType =CommandType.StoredProcedure;

    cmd.Parameters.Add(new SqlParameter("@ID", AdminDropDown.SelectedValue));

    //cmd.Connection.Open();
    //cmd.ExecuteNonQuery();

    SqlDataAdapter ad = new SqlDataAdapter(cmd);

    ad.Fill(dt);     

    if (dt.Rows.Count > 0)
    {
        //If you want to get mutiple data from the database then you need to write a simple looping
        txtFirstName.Text = dt.Rows[0]["FirstName"].ToString();

        txtMiddleName.Text = dt.Rows[0]["MiddleName"].ToString();

        txtLastName.Text = dt.Rows[0]["LastName"].ToString();

        txtSignature.Text = dt.Rows[0]["Signature"].ToString();

    }

    ad.Dispose();  // e.g. this way

    cmd.Connection.Close();
}

... or much better (as you already did with SqlConnection conn) put it into a using block:

using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
{
  // put the code using ad here, ad is automatically disposed
}