无法将参数值从字符串转换为Int32错误

Question

My issue is that while submitting the data into the database I am getting error as

Failed to convert parameter value from a String to a Int32.

Here is my code:-

protected void btnSubmit_Click(object sender, EventArgs e)
{
        SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["DefaultCSRConnection"].ConnectionString);
        foreach (GridViewRow row in ImagesGrid.Rows)
        {
            var title = row.FindControl("txtTitle") as TextBox;
            var description = row.FindControl("txtDescription") as TextBox;
            var imageFile = row.FindControl("flUpload") as FileUpload;

            using (SqlCommand cmd = conn.CreateCommand())
            {
                conn.Open();
                SqlCommand cmd1 = new SqlCommand("Insert into tbl_galleries_stack (gallery_id,img_title,img_desc,img_path,IsDefault) values (@gallery_id,@img_title,@img_desc,@img_path,@IsDefault)", conn);
                cmd1.Parameters.Add("@gallery_id", SqlDbType.Int).Value = ddlgallery.SelectedItem.Text;
                cmd1.Parameters.Add("@img_title", SqlDbType.VarChar).Value = title;
                cmd1.Parameters.Add("@img_desc", SqlDbType.VarChar).Value = description;
                cmd1.Parameters.Add("@img_path", SqlDbType.NVarChar).Value = imageFile;
                cmd1.Parameters.Add("@IsDefault", SqlDbType.Bit).Value = Convert.ToInt32(chkDefault.Checked);
                cmd1.ExecuteNonQuery();
                conn.Close();
                ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('Teachers profile added sucessfully');window.location ='csrgalleriesstack.aspx';", true);
            }

        }
}

I tried changing to Int32 for the checkbox but it is not working.

Answer 1

Looks like problem on that line;

cmd1.Parameters.Add("@gallery_id", SqlDbType.Int).Value = ddlgallery.SelectedItem.Text;

SelectedItem.Text is string but you try to insert that value to an int column since you typed as SqlDbType.Int .

If your column is already a character typed, you need to use the right SqlDbType enum value. But since your parameter name gallery_id , I strongly suspect it is a numeric value. In such a case, you need to convert that ddlgallery.SelectedItem.Text value to Int32 if it is a valid integer.

Also as Habib mentioned , you don't need to use Convert.ToInt32 in your last parameter. Since Checked returns bool , it is correctly mapped with Bit type on SQL Server.

And use using statement for your SqlConnection as you did for SqlCommand .

Answer 2

Have you tried using Convert.ToInt32(ddlgallery.SelectedItem.Text); instead of passing Text directly?

Answer 3

ddlgallery.SelectedItem.Text is causing problem for you.

Try ddlgallery.SelectedItem.Value , even if it gives you a problem, then try

Convert.ToInt32(ddlgallery.SelectedItem.Value) .

Usually dropdown lists show text in the front end, but they have an integer value associated with them, which can be extracted using ddlgallery.SelectedItem.Value

Regards

Answer 4

Actually the issue was not in the gallery_id , The issue was, I had to send the filename with the path. like this

cmd1.Parameters.Add("@img_path", SqlDbType.NVarChar).Value = "~/Images/" + imageFile.FileName;

And that worked for me.

So my final code was like below:-

protected void btnSubmit_Click(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["DefaultCSRConnection"].ConnectionString);
        foreach (GridViewRow row in ImagesGrid.Rows)
        {   
            var title = row.FindControl("txtTitle") as TextBox;
            var description = row.FindControl("txtDescription") as TextBox;
            var imageFile = row.FindControl("flUpload") as FileUpload;
            var chkDefault = row.FindControl("chkDefault") as CheckBox;
            using (SqlCommand cmd = conn.CreateCommand())
            {
                conn.Open();
                SqlCommand cmd1 = new SqlCommand("Insert into tbl_galleries_stack (gallery_id,img_title,img_desc,img_path,isDefault) values (@gallery_id,@img_title,@img_desc,@img_path,@isDefault)", conn);
                cmd1.Parameters.Add("@gallery_id", SqlDbType.Int).Value = Convert.ToInt32(ddlgallery.SelectedValue);
                cmd1.Parameters.Add("@img_title", SqlDbType.NVarChar).Value = title.Text;
                cmd1.Parameters.Add("@img_desc", SqlDbType.NVarChar).Value = description.Text;
                if (imageFile.HasFile)
                {
                    imageFile.SaveAs(Server.MapPath("~/GalleryImages/") + imageFile.FileName);
                    cmd1.Parameters.Add("@img_path", SqlDbType.NVarChar).Value = "~/GalleryImages/" + imageFile.FileName;
                }
                cmd1.Parameters.Add("@IsDefault", SqlDbType.Bit).Value = chkDefault.Checked;
                cmd1.ExecuteNonQuery();
                conn.Close();
                ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('Teachers profile added sucessfully');window.location ='csrgalleriesstack.aspx';", true);
            }

        }
    }